Mechanical Engineering - Machine Design Quiz (or) MCQ

1 .

Which of the following parameters can be obtained by tension test of a standard specimen?

A)

Yield Strength

B)

Percentage Reduction in area

C)

Proportional Limit

D)

All of the above

Correct Answer : Proportional Limit

Explanation : Tension test determines the parameters related to stress strain curve and also reduction and elongation in area and length can be found respectively.

2 .

Ductile cast iron is

A)

Also called nodular cast iron

B)

Also called spheroidal graphite cast iron

C)

Carbon is present in form of spherical nodules

D)

All of the above

Correct Answer : All of the above

Explanation : Ductile cast iron, also called as nodular cast iron or spheroidal cast iron consists of carbon in the form of spherical nodules in a ductile matrix.

3 .

Which of the following is the definition of Compliance?

A)

Inverse of Stiffness

B)

Inverse of Rigidity

C)

Proportional to elastic Limit

D)

None of the above

Correct Answer : Inverse of Stiffness

4 .

Yield strength is defined as the maximum stress at which a marked increase in elongation occurs without increase in________

A)

Strength

B)

Load

C)

Hardness

D)

Toughness

Correct Answer : Load

Explanation : Yield strength is the strength at which strain increases. Now as the strength is constant, therefore load is constant.

5 .

The sleeve or muff coupling is designed as a

A)

solid shaft

B)

hollow shaft

C)

dun cylinder

D)

thick cylinder

Correct Answer : hollow shaft

6 .

Screws used for power transmission should have

A)

high efficiency

B)

Low efficiency

C)

strong teeth

D)

very fine threads

Correct Answer : high efficiency

7 .

When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90Â°, then they are known as

A)

mitre gears

B)

angular bevel gears

C)

crown bevel gears

D)

internal bevel gears

Correct Answer : crown bevel gears

8 .

For the materials which do not exhibit a well-defined yield points, the yield strength is defined as the stress corresponding to a permanent set of how much percentage of gauge length?

A)

0.1

B)

0.2

C)

0.3

D)

0.4

Correct Answer : 0.2

Explanation : Generally for all the practical purpose, an offset of 0.2% of gauge length is considered.

9 .

Proof strength is defined as the stress which will produce a permanent extension of how much percentage in the gauge length of the standard test specimen.

A)

0.1

B)

0.2

C)

0.3

D)

0.4

Correct Answer : 0.1

Explanation : Proof strength is used in design of fasteners. It corresponds to 0.1% permanent deformation of gauge length.

10 .

Grey Cast iron is formed when

A)

Carbon content in the alloy is less than the amount that can be dissolved

B)

Carbon content in the alloy is equal to the amount that can be dissolved in the alloy

C)

Carbon content in the alloy exceeds the amount that can be dissolved

D)

None of the above

Correct Answer : Carbon content in the alloy exceeds the amount that can be dissolved

11 .

White cast iron is formed when

A)

No iron carbide is formed

B)

Graphite flakes are formed

C)

Both (A) and (B)

D)

Most of the carbon content in the alloy forms iron carbide

Correct Answer : Most of the carbon content in the alloy forms iron carbide

Explanation : White cast iron is formed when most carbon in alloy forms iron carbide and there are no graphite flakes.

12 .

The term high alloy steels is used for alloy steels containing more than ___ of alloying elements.

A)

10%

B)

20%

C)

50%

D)

70%

Correct Answer : 10%

Explanation : The term high alloy steels is used when alloying elements exceed 10%.Low and medium alloy steels are those when this figure is less than 10%.

13 .

Which of the following property is affected by heat treatment?

A)

Hardness

B)

Strength

C)

Ductility

D)

All of the above

Correct Answer : All of the above

Explanation : Heat treatment involves changes in the micro structure and hence all the internal properties are effected.

14 .

Annealing involves heating the component to a temperature

A)

Equal to critical temperature

B)

Slightly less than critical temperature

C)

Slightly above the critical temperature

D)

None of the above

Correct Answer : Slightly above the critical temperature

Explanation : In annealing, component is heated to a temperature above than critical temperature.

15 .

Which of the following is true?

A)

Annealing improves ductility

B)

Normalising improves grain structure

C)

Rate of cooling in normalising is faster then in annealing

D)

All of the above

Correct Answer : All of the above

Explanation : In annealing, the furnace is switched off and component cools slowly. In normalising, component is air cooled.

16 .

Relative density of aluminium is roughly _______ of steel

A)

equal

B)

one-third

C)

one-fifth

D)

one-tenth

Correct Answer : one-third

Explanation : Aluminium alloy=2.7 Steel=7.9.

17 .

Which of the following statement is true

A)

Cast aluminium alloys are specified by a four digit system while wrought alloys by a five digit system

B)

Cast aluminium alloys are specified by a six digit system while wrought alloys by a five digit system

C)

Cast aluminium alloys are specified by a five digit system while wrought alloys by a six digit system

D)

Cast aluminium alloys are specified by a five digit system while wrought alloys by a four digit system

Correct Answer : Cast aluminium alloys are specified by a four digit system while wrought alloys by a five digit system

Explaination : Standard set for nomenclature.

18 .

Which of the following are true for aluminium

A)

Low specific gravity

B)

Corrosion resistance

C)

High thermal conductivity

D)

All of the above

Correct Answer : All of the above

19 .

In alloy 4450, 2nd digit represents?

A)

average percentage of major alloying elements

B)

average percentage of minor alloying elements

C)

average percentage of major alloying elements, halved and rounded off

D)

average percentage of minor alloying elements, halved and doubled

Correct Answer : average percentage of major alloying elements, halved and rounded off

Explanation : Second digit is used to represent major alloying element.

20 .

Which of the following are true for copper alloys_________.

A)

Has good corrosion resistance

B)

Can be easily cast and machined

C)

Posses excellent thermal and electrical conductivity

D)

All of the above

Correct Answer : All of the above

Explanation : Properties of copper.

21 .

Which of the following contain copper

A)

bronze

B)

gunmetal

C)

monel metal

D)

each of the mentioned

Correct Answer : each of the mentioned

Explanation : All the mentioned alloys contain copper to some extent.

22 .

As the amount of zinc increases

A)

strength of brass increases and ductility decrease

B)

strength of brass increases and ductility increase

C)

strength of brass decreases and ductility increases

D)

strength of brass decreases and ductility decreases

Correct Answer : strength of brass increases and ductility decrease

Explanation : Brass contains zinc and copper. Zinc affects strength with direct increase in strength with increase of zinc content.

23 .

Which of the following are true for aluminium bronze

A)

difficult to cast

B)

contain 5-10% aluminium

C)

excellent corrosion and is also called imitation gold

D)

All of the above

Correct Answer : All of the above

Explanation : Color of aluminium bronze is similar to gold. Other two are the properties of alloys.

24 .

Ceramics consist of______.

A)

hydrogen bonding

B)

ionic & covalent bonding

C)

covalent bonding

D)

None of the above

Correct Answer : ionic & covalent bonding

Explanation : Ceramics consists of ionic and covalent bonds only.There is no hydrogen compound so no case of H boding.

25 .

Which of the following properties are true for ceramics.

A)

excellent wear

B)

lower friction loss

C)

light weight construction with low inertia force

D)

All of the above

Correct Answer : All of the above

26 .

Which of the following is a thermosetting polymer?

A)

Polyesters

B)

PVC

C)

PTFE

D)

Nylon

Correct Answer : Polyesters

27 .

Paraffin wax is represented by__________.

A)

C18H35

B)

C18H36

C)

C18H38

D)

C18H40

Correct Answer : C18H38

Explanation : Paraffin wax in a semi solid stage is represented by C18H38.

28 .

Which of the following are true about plasticity?

A)

Permanent Deformation

B)

Plastic deformation is greater than elastic deformation

C)

Ability to retain deformation under load or after removal of load

D)

All of the above

Correct Answer : All of the above

Explanation : This is the basic definition of plasticity.

29 .

Which of the following facts are true for resilience?

A)

Ability of material to absorb energy when deformed plastically

B)

Ability of material to absorb energy when deformed elastically

C)

Ability to retain deformation under the application of load or after removal of load

D)

None of the above

Correct Answer : Ability of material to absorb energy when deformed elastically

Explanation : Toughness is ability to store energy till proportional limit during deformation and to release this energy when unloaded.

30 .

Which of the following are true for toughness

A)

Measured by Izod & Charpy test

B)

Decreases with the increase in temperature

C)

Ability of material to absorb energy before fracture

D)

All of the above

Correct Answer : All of the above

Explanation : Toughness is measure of energy stored till fracture occurs. With rise of temperature, molecular bonds weakens and fracture occurs at a lesser load, hence area under stress strain curve decreases.

31 .

Modulus of resilience is defined as

A)

Strain energy per unit area

B)

Independent of strain energy

C)

Strain energy per unit volume

D)

None of the above

Correct Answer : Strain energy per unit volume

Explanation : Modulus of resilience is strain energy per unit volume.

32 .

Which of the following are true about low carbon steels?

A)

Are soft and ductile

B)

Also called as mild steel

C)

Carbon content < 0.3%

D)

All of the above

Correct Answer : All of the above

Explanation : Low carbon steels contain carbon <0.3%. Because of low carbon, it is soft and ductile.

33 .

Which of the following given steels is popular with the name of machinery steel?

A)

Low carbon steel

B)

Medium carbon steel

C)

High carbon steel

D)

None of the above

Correct Answer : Medium carbon steel

34 .

Which of the following steel given in options respond fastest and easily to heat treatment?

A)

40C8

B)

30C8

C)

10C4

D)

7C4

Correct Answer : 40C8

Explanation : Alloys with higher carbon % respond willingly to heat treatment.

35 .

Quenching_________.

A)

Cooling rapidly

B)

Increases hardness

C)

Consists of heating the component to critical temperature

D)

All of the above

Correct Answer : All of the above

Explanation : During quenching, component is rapidly cooled which leads to formation of martensite. Hence hardness increases.

36 .

Nickel addition in alloys

A)

Increases toughness

B)

Increases hardenability and impact resistance

C)

Limit grain growth during heat treatment process

D)

All of the above

Correct Answer : All of the above

Explanation : Nickel addition increases toughness by limiting grain growth.

37 .

Which of the following are not true for carbo nitriding?

A)

Component is heated in range of 650 to 920â€™C

B)

Introducing carbon and nitrogen at surface layer

C)

This process gives a lower wear resistance compared to case carburising process

D)

Cyaniding is similar to carbo nitriding except that the medium is liquid

Correct Answer : This process gives a lower wear resistance compared to case carburising process

Explanation : Carbo nitriding gives wear resistance greater than compared to case carburising.

38 .

Which of the following are true for nitriding?

A)

Gaseous or liquid medium

B)

Nascent oxygen is involved

C)

Temperature range 490 to 590â€™C

D)

All of the above

Correct Answer : All of the above

Explanation : In nitriding nascent oxygen is acted on the surface of the product at a temperature of 490::590’C in a gaseous or liquid medium.

39 .

An aluminium alloy casting with 9.8% Cu, 1.0% Fe and 0.25% Mg

A)

Alloy 2585

B)

Alloy 2686

C)

Alloy 3584

D)

Alloy 3586

Correct Answer : Alloy 2585

Explanation : 1st digit=2(Copper) ; 2nd digit=9.8/2=5 ;3rd digit=8(Iron); 4th digit=5(Magnesium).

40 .

In alloy 4450, 4 represents?

A)

Zinc

B)

Silicon

C)

Aluminium

D)

Manganese

Correct Answer : Silicon

Explanation : In alloy nomenclature,1=Al;2=Cu;3=Mn;4=Si;5=Mg.

41 .

Which of the following are true for die casting alloys?

A)

surface finish is excellent

B)

process used for a metal with low melting point

C)

this process consists of forcing the molten metal into a closed metal die

D)

All of the above

Correct Answer : All of the above

42 .

Monel metal is a copper nickel alloy of __% nickel and __%copper.

A)

20,80

B)

32,65

C)

65,32

D)

80,20

Correct Answer : 65,32

43 .

Gunnmetal is an alloy of copper which __ % tin and __% zinc.

A)

10,2

B)

5,4

C)

4,5

D)

2,10

Correct Answer : 10,2

Explanation : Zinc is used to improve fluidity during casting and hence is kept lesser than tin.

44 .

Which of the following statements for phosphorus bronze is true?

A)

contains 0.2% phosphorus

B)

use for worm wheels and bearings

C)

phosphorus increases tensile strength

D)

All of the above

Correct Answer : All of the above

Explanation : It has good tensile strength, corrosion resistance and is used for bearings.

45 .

Flame hardening involves

A)

Quenching after heatingv

B)

Minimum case depth is 1mm

C)

Heating the surface above the trAnswerformation range

D)

All of the above

Correct Answer : All of the above

Explanation : Flame Hardening is a process of heating the surface with a flame above critical temperature and then quenching it.

46 .

Induction hardening process involves

A)

Case depth minimum of 2mm are produced

B)

Heating surface by induction in field of alternating current

C)

Heating surface by induction in field of invariable current

D)

None of the above

Correct Answer : Heating surface by induction in field of alternating current

Explanation : Heating can only be done in presence of alternating current and not constant current.

47 .

Which of the following are true for high carbon steels?

A)

Carbon content=0.4%

B)

Easy to weld

C)

Respond readily to heat treatments

D)

Have much ductility as compared to low and medium carbon steels

Correct Answer : Respond readily to heat treatments

Explanation : High carbon steel have carbon % >0.5 and hence have less ductility. They are difficult to weld.

48 .

Which of the steel in given options is best suited for auto mobile bodies and hoods?

A)

7C4

B)

10C4

C)

30C8

D)

40C8

Correct Answer : 7C4

Explanation : For automobile application like manufacturing bodies, ductile material is preferred.

49 .

In the designation 'xCb' which of the following are true?

A)

b indicates 100 times the average % of carbon

B)

b indicates 100 times the average percentage of manganese

C)

x indicates 100 times the average % of carbon

D)

x indicates 10 times the average percentage of carbon while b indicates 100 times the average percentage of manganese

Correct Answer : x indicates 100 times the average % of carbon

Explanation : X indicates 100 times carbon % and b indicates 10 times manganese %.

50 .

Which of the following are true?

A)

7C4 grade steel is more ductile than 10C4

B)

Hardness of 30C8 is greater than of 40C8

C)

Yield strength of 40C8 is greater than of 30C8

D)

None of the above

Correct Answer : 7C4 grade steel is more ductile than 10C4

51 .

Which process allows controlling grain structure of the product?

A)

Casting

B)

Forging

C)

Die Casting

D)

None of the above

Correct Answer : Forging

Explanation : In casting metal is in fluid state and hence impossible to control the grain structure.

52 .

In forging, metal is in which of the following stage?

A)

Plastic

B)

Rigid

C)

Elastic

D)

Can be in any stage

Correct Answer : Plastic

Explanation : Forging is the working of metal in plastic range.

53 .

Among casting, forging and forging which has the slowest rate of production?

A)

Forging

B)

Casting

C)

Machining

D)

None of the above

Correct Answer : Machining

Explanation : Machining each part is very time consuming.

54 .

Maximum carbon content in welding is usually limited to

A)

0.22%

B)

0.8%

C)

1.5%

D)

2%

Correct Answer : 0.22%

Explanation : With increase of carbon, welding becomes difficult as weld becomes susceptible to cracks.

55 .

Which of the following is not a classification of fit?

A)

Clearance

B)

Enjoining

C)

Transition

D)

Interference

Correct Answer : Enjoining

Explanation : Simple classification of fits is down in 3 categories.

56 .

Which of the following always provides a positive clearance between the hole and the shaft over the entire range of tolerances?

A)

Transition

B)

Interference

C)

Both (A) and (B)

D)

Clearance

Correct Answer : Clearance

57 .

Hot working or cold working, which reduces strain hardening and residual stresses.

A)

Hot working

B)

Cold working

C)

Both have equal effect

D)

Impossible to detect

Correct Answer : Hot working

Explanation : In hot working grains are re arranges as per requirement and no residual stresses.

58 .

The temperature at which new stress free grains are formed in the metal is called the ______ temperature.

A)

Solidification

B)

Crystallization

C)

Recrystallization

D)

None of the above

Correct Answer : Recrystallization

Explanation : Definition of recrystallization temperature.

59 .

Tolerance for a shaft of 50mm diameter as the basic size, with the fundamental deviation denoted by g and tolerance of grade 7 is represented as?

A)

7g50

B)

50g7

C)

g50,7

D)

None of the above

Correct Answer : 50g7

Explanation : First fundamental deviation is written followed by diameter and grade.

60 .

In this case, tolerance zone of hole is entirely below that of the shaft.

A)

Clearance

B)

Enjoining

C)

Interference

D)

None of the above

Correct Answer : Interference

Explanation : Interference fit provides a positive clearance and hence tolerance zone of hole is below that of shaft.

61 .

Which of the following are true for system of tolerances to the shaft and the hole?

A)

In hole-basis system, various shafts are associated with a single hole

B)

In shaft-basis system, various shafts are associated with a single hole

C)

In hole-basis system as well as shaft-basis system, various shafts are associated with multiple holes

D)

None of the above

Correct Answer : In hole-basis system, various shafts are associated with a single hole

Explanation : As per the standards.

62 .

How many grades of tolerances are there according to BIS system fits and tolerances?

A)

12

B)

14

C)

16

D)

18

Correct Answer : 18

63 .

Which of the following are true for fundamental deviation?

A)

Small letter is used for both holes and shaft

B)

Gives location of tolerance zone

C)

Capital letter is used for both holes and shafts

D)

None of the above

Correct Answer : Gives location of tolerance zone

Explanation : Tolerance zone is depicted by deviation while magnitude is depicted by grade.

64 .

A mechanical component may fail as a result of which of the following

A)

fracture

B)

elastic deflection

C)

general yielding

D)

each of the mentioned

Correct Answer : elastic deflection

Explanation : Failing simply means unable to perform its function satisfactorily.

65 .

For cast iron components, which of the following strength are considered to be the failure criterion?

A)

Yield Strength

B)

Endurance limit

C)

Ultimate tensile strength

D)

None of the above

Correct Answer : Ultimate tensile strength

66 .

For components made of ductile materials like steel, subjected to static loading which of the following strength is used as a failure of criterion?

A)

Yield strength

B)

Endurance limit

C)

Ultimate strength

D)

None of the above

Correct Answer : Yield strength

Explanation : In elastic material there is considerable plastic deformation at yielding point.

67 .

If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm²Find the maximum amount of shear stress to which the body is subjected.

A)

22.4mm

B)

25mm

C)

26.3mm

D)

27.2mm

Correct Answer : 22.4mm

Explaination : τ(max)=√( [σ(x)-σ(y) ]²/2² + τ²).

68 .

If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 10N/mm². Find the inclination of the plane in which shear stress is maximal.

A)

30’

B)

45’

C)

60’

D)

75’

Correct Answer : 45’

Explaination : tan (2Ç¾)=2τ/[σ(x) – σ(y)].

69 .

If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the maximum normal stress.

A)

90

B)

92.4

C)

94.2

D)

96

Correct Answer : 92.4

Explaination : σ=[σ(x) +σ(y)]/2 + √( [σ(x)-σ(y) ]²/2² + τ²).

70 .

If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the minimum normal stress.

A)

50.6

B)

48.2

C)

47.6

D)

45.4

Correct Answer : 47.6

Explaination : σ=[σ(x) +σ(y)]/2 – √( [σ(x)-σ(y) ]²/2² + τ²).

71 .

Cotter joint is used when the members are subjected to which type of stresses?

A)

Axial tensile

B)

Axial compressive

C)

Axial tensile or compressive

D)

None of the above

Correct Answer : Axial tensile or compressive

Explanation : Cotter joint is used when axial forces are applied.

72 .

Which of the following is not a part of cotter joint?

A)

Collar

B)

Cotter

C)

Spigot

D)

Socket

Correct Answer : Collar

Explanation : There is no point of mentioning collar alone in a cotter joint. It has to be a spigot collar or socket collar.

73 .

Determine the width of the cotter used in cotter joint connecting two rods subjected to axial load of 50kN and permissible shear stress in cotter is 50N/(mm² ). Given thickness of cotter=10mm

A)

25mm

B)

5omm

C)

100mm

D)

150mm

Correct Answer : 5omm

Explaination : Cotter is subjected to double shear hence width=P/(2*τ*t).

74 .

If joint is to fail by crushing of socket collar then estimate the diameter of socket collar. Given Permissible compressive stress= 126.67 N/mm².; Spigot dia=65mm; thickness 0f collar=15mm

A)

131mm

B)

139mm

C)

141mm

D)

149mm

Correct Answer : 131mm

Explaination : Compressive stress= P/ [(socket dia-spigot dia)*thickness]

75 .

The distance between fulcrum and dead weights is 100mm. Dead weights are of 2945.2N. An effort of 294.52N acts on the other hand. Find the distance between the fulcrum and other end of the lever.

A)

10mm

B)

100mm

C)

1000mm

D)

10000mm

Correct Answer : 100mm

Explaination : F â‚‚xlâ‚‚ =Fâ‚ xlâ‚.

76 .

A maximum of how many roads may be connected using a knuckle joint?

A)

2

B)

3

C)

4

D)

5

Correct Answer : 3

Explanation : In rare explanation, two rods with forks and one rod with eye is connected.

77 .

Which of the following are important parts of knuckle joint?

A)

Eye

B)

C)

Fork

D)

Each of the mentioned

Correct Answer : Each of the mentioned

Explanation : All the mentioned parts are important components of knuckle joint.

78 .

Calculate the diameter of pin from shear consideration with maximum shear stress allowed is 40NN/mmÂ² and an axial tensile force of 50kN is acting on the rod.

A)

39mm

B)

44mm

C)

49mm

D)

52mm

Correct Answer : 39mm

Explanation : As the pin is subjected to double shear diameter (D) = √(2P/π x τ) = 38.80mm.

79 .

If any cross section is subjected to direct tensile stress and bending stress, then find the dimension of cross section. Given length & breadth are t and 2t respectively. F=25kN acts on the top fibre of the cross section, M=F x t . Also maximum allowable tensile stress =100N/mm².

A)

25.5mm

B)

27.55mm

C)

30.2mm

D)

None of the above

Correct Answer : 25.5mm

Explaination : σ= [P/A] + [My/I], where y=t & I=t(2t)á´²/12.

80 .

If any cross section is subjected to direct tensile stress and bending stress, then find the dimension of cross section. Given length & breadth are t and 2t respectively. F=25kN acts on the top fibre of the cross section, M=F x t . Also maximum allowable tensile stress =100N/mm².

A)

25.5mm

B)

27.55mm

C)

30.2mm

D)

None of the above

Correct Answer : 25.5mm

Explaination : σ= [P/A] + [My/I], where y=t & I=t(2t)á´²/12.

81 .

If knuckle joint is to fail by crushing failure of pin in fork, then determine the diameter of knuckle pin when 50kN axial tensile force act on rods. Given: Max allowable compressive stress=25N/mm², thickness of each eye of fork=25mm.

A)

40mm

B)

50mm

C)

60mm

D)

70mm

Correct Answer : 40mm

Explaination : d=P/2aσ = 40mm.

82 .

The critical value at which crack extension occurs is called

A)

Toughness

B)

Fracture Toughness

C)

Stress Intensity Factor

D)

None of the above

Correct Answer : Fracture Toughness

Explanation : Fracture toughness is the critical value of stress intensity at which crack extension occurs.

83 .

How many modes are there for crack propagation?

A)

2

B)

3

C)

4

D)

5

Correct Answer : 3

Explanation : Opening, sliding and tearing are the 3 modes.

84 .

If for a curved beam of trapezoidal cross section, radius of neutral axis is 89.1816mm and radius of centroidal axis is 100mm, then find the bending stress at inner fibre whose radius is 50mm. Area of cross section of beam is 7200mm² and the beam is loaded with 100kN of load.

A)

97.3

B)

95.8

C)

100.6

D)

None of the above

Correct Answer : 100.6

Explaination : e=100-89.816=10.8184mm, h=89.1816-50=39.1816mm, M=100 x 100 N-m
Therefore σ=Mh/AeR or σ=10000 x 39.1816/ [7200 x 10.8184 x 50] or σ=100.6N/mm².

85 .

The critical buckling load depends upon which of the following parameters?

A)

Yield strength

B)

Radius of gyration

C)

Each of the mentioned

D)

Modulus of elasticity

Correct Answer : Each of the mentioned

Explanation : It depends on moment of inertia(which further depends on radius of gyration), elasticity and yield strength.

86 .

Which of the following relationship is true? (p=Poisson's ratio)

A)

E=G (2+p)

B)

E= 2(G+ p)

C)

Both (A) and (B)

D)

E=2G (1+p)

Correct Answer : E=2G (1+p)

87 .

According to principal stress theory, which option represents the correct relation between yield strength in shear (YSS) and the yield strength in tension (YST)?

A)

YSS=0.5YST

B)

YST=0.5YSS

C)

YST=0.577YSS

D)

YSS=0.577YST

Correct Answer : YSS=0.5YST

Explanation : Shear diagonal is at 45’ and by equation of shear stress theory, the required relation is obtained.

88 .

A beam subjected to bending moment undergoes which of the following stresses?

A)

Tensile

B)

Compressive

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

Explanation : The portion above the neutral axis is under compression and the portion below it is under tensile stress.

89 .

The bending stress varies _______ with the distance from the neutral axis.

A)

Squarely

B)

Linearly

C)

Inversely

D)

Bending stress is independent of distance from the neutral axis

Correct Answer : Linearly

Explanation : Bending Stress= (Bending Moment x distance from neutral axis/ Moment of inertia).

90 .

The total strain energy for a unit cube subjected to three principal stresses is given by?

A)

U= [(ÏƒÎ) â‚ + (ÏƒÎ) â‚‚+ (ÏƒÎ) â‚ƒ]/3

B)

U= [(Ïƒâ‚Â²+Ïƒâ‚‚Â²+Ïƒâ‚ƒÂ²)/2E] â€“ (Ïƒâ‚Ïƒâ‚‚+Ïƒâ‚‚Ïƒâ‚ƒ+Ïƒâ‚ƒÏƒâ‚)2Î¼

C)

U= [(ÏƒÎ) â‚ + (ÏƒÎ) â‚‚+ (ÏƒÎ) â‚ƒ]/4

D)

None of the above

Correct Answer : U= [(Ïƒâ‚Â²+Ïƒâ‚‚Â²+Ïƒâ‚ƒÂ²)/2E] â€“ (Ïƒâ‚Ïƒâ‚‚+Ïƒâ‚‚Ïƒâ‚ƒ+Ïƒâ‚ƒÏƒâ‚)2Î¼

Explanation : U= [(σÎ) â‚ + (σÎ) â‚‚+ (σÎ) â‚ƒ]/2 is the basic formula. After substituting values of Îâ‚, Îâ‚‚ and Îâ‚ƒ, we get the expression b.

91 .

The region of safety in maximum shear stress theory contains which of the given shape

A)

Hexagon

B)

Square

C)

Rectangle

D)

None of the above

Correct Answer : Hexagon

Explanation : In maximum shear stress theory we have the following equations: σ1= ±S(yt)
σ2= ±S (yt), σ1 – σ2 =±S (yt) assuming S(yt)=S(yc).

92 .

If compressive yield stress and tensile yield stress are equivalent, then region of safety from maximum principal stress theory is of which shape?

A)

Ellipse

B)

Circle

C)

Rectangle

D)

Square

Correct Answer : Square

Explanation : The equation of four lines is given by σ1=± S(yt), σ2=±S(yc) N

93 .

A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Longer arm is of length 500mm. Calculate the reaction or force acting on the fulcrum.

A)

6.1

B)

6.8

C)

5.1

D)

5.8

Correct Answer : 5.1

Explanation : Force required for raising at longer end is found by F â‚‚xlâ‚‚ =Fâ‚ xlâ‚. Reaction at fulcrum is √ (Fâ‚²+Fâ‚‚²) as the two forces are perpendicular.

94 .

A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the length of the pin.

A)

20mm

B)

25.5mm

C)

30mm

D)

35.5mm

Correct Answer : 25.5mm

Explaination : R=p x d x L. Here R=√ (Fâ‚²+Fâ‚‚²).

95 .

A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the shear stress in the pin.

A)

8.12

B)

8.51

C)

9.12

D)

9.51

Correct Answer : 8.12

Explaination : τ=R/(2 x π x d²/4) as the pin is subjected to double shear. Also R=√ (Fâ‚²+Fâ‚‚²) and F â‚‚xlâ‚‚ =Fâ‚ xlâ‚.

96 .

A bottle opener belongs to which class of the levers.

A)

Fulcrum in the middle

B)

Effort in the middle

C)

Resistance in the middle

D)

None of the above

Correct Answer : Resistance in the middle

Explanation : In a bottle opener fulcrum can be considered at the end and resistance in middle as the actual work is done on the bottle cap which lies in middle of opener.

97 .

How many classes of levers are there?

A)

2

B)

3

C)

4

D)

5

Correct Answer : 3

Explanation : The three classes are Fulcrum in the middle, Resistance in the middle and Effort in the middle.

98 .

If a hollow steel tube is heated from a temperature of 25’C to 250’C then fid the expansion of tube if area of the cross section is 300mm²,length of tube=200mm and coefficient of thermal expansion is 10.8 x 10â»â¶ per â°C.

A)

0.486mm

B)

0.878mm

C)

1.22mm

D)

1.52mm

Correct Answer : 0.486mm

Explaination : Expansion=á¼€xlxâˆ†T= 10.8 x 10â»â¶ x 200 x 225=0.486mm.

99 .

A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm² and considering combined effect of direct stress and bending stress.

A)

17.9mm

B)

18.1mm

C)

14.35mm

D)

15.8mm

Correct Answer : 14.35mm

Explaination : σ(b)=Mh/ AeR or σ(b)=1000x4Dx(4D-0.2D-3.5D)/ 0.8D²x0.02Dx3.5D , σ(b)=21428.6/D²
DirectTensile Stress=1000/0.8D² or σ (t) =1250/D²
Total stress=22678.6/D² N/mm²= 110 or D=14.35mm.

100 .

A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm².Considering only bending stress.

A)

13.95mm

B)

14.80mm

C)

16.5mm

D)

17.2mm

Correct Answer : 13.95mm

Explaination : σ(b)=Mh/ AeR or σ(b)=1000x4Dx(4D-0.2D-3.5D)/ 0.8D²x0.02Dx3.5D , σ(b)=21428.6/D²
21428.6/D² = 110 or D=13.95mm.

101 .

If a flat plate with a circular hole is subjected to tensile force, then its theoretical stress concentration factor is?

A)

1

B)

2

C)

3

D)

4

Correct Answer : 3

Explanation : For any ellipse, K=1+2 x (semi major axis/semi minor axis).

102 .

For an elliptical hole on a flat plate, if width of the hole in direction of the load decrease, Stress Concentration Factor will______

A)

Increase

B)

Decrease

C)

Remains constant

D)

Canâ€™t be determined. Varies from material to material

Correct Answer : Increase

Explanation : K=1+2 x (semi major axis/semi minor axis. Hence K is inversely proportional to the semi minor axis.

103 .

In which of the following case stress concentration factor is ignored?

A)

Ductile material under static load

B)

Brittle material under static load

C)

Ductile material under fluctuating load

D)

Brittle material under fluctuating load

Correct Answer : Ductile material under static load

Explanation : In ductile materials under static load, there is plastic deformation near yielding point and hence redistribution of stresses take place. The plastic deformation is restricted to a smaller area and hence no perceptible damage take place.

104 .

A flat plate 30mm wide and “t”mm wide is subjected to a tensile force of 5kN. The plate has a circular hole of diameter 15mm with the centre coinciding with the diagonal intersection point of the rectangle. If stress concentration factor=2.16, find the thickness of the plate if maximum allowable tensile stress is 80N/mm².

A)

8mm

B)

9mm

C)

10mm

D)

12mm

Correct Answer : 9mm

Explaination : σ=P/ (w-d) x t or σ=5000/(30-15)xt ; σ(max)=K x σ or σ(max)=2.16 x σ or σ(max)=720/t; Also σ(max)=80.

105 .

Which of the following reduces the stress concentration?

A)

Use of multiple notches

B)

Drilling additional holes

C)

Removal of undesired material

D)

All of the above

Correct Answer : All of the above

Explanation : All of the above options reduce the sharp bending of a force flow line.

106 .

Use of multiple notches in a V shaped flat plate will

A)

No effect

B)

Reduce the stress concentration

C)

Increase the stress concentration

D)

Cannot be determined

Correct Answer : Reduce the stress concentration

Explanation : The sharp bending of a force flow line is reduced due to multiple notches.

107 .

The stress represented by sin (t) + 1 belongs to which category?

A)

Reversed Stresses

B)

Alternating stresses

C)

Repeated Stresses

D)

Fluctuating Stresses

Correct Answer : Repeated Stresses

Explanation : The minimum stress value is zero and hence is belongs to Repeated Stress category.

108 .

The stress represented by sin (t) + 2 belongs to which category?

A)

Repeated Stresses

B)

Reversed Stresses

C)

Both (A) and (B)

D)

Fluctuating Stresses

Correct Answer : Fluctuating Stresses

Explanation : The mean as well as the amplitude value is non zero hence it belongs to Fluctuation Stress Category.

109 .

The phenomenon of decreased resistance of the materials to fluctuating stresses is the main characteristic of _____ failure.

A)

Fatigue

B)

Fracture

C)

Yielding

D)

None of the above

Correct Answer : Fatigue

Explanation : Fatigue failure of the material is the failure at low stress levels under fluctuating syresses.

110 .

If the mean stress value for a sinusoidal stress function is zero, then this type of stress falls in which category?

A)

Repeated Stresses

B)

Reversed Stresses

C)

Alternating Stresses

D)

Fluctuating Stresses

Correct Answer : Reversed Stresses

Explanation : If mean is to be zero, then there must be compressive as well as tensile stresses and hence belongs to reversed stresses category.

111 .

The stress represented by sin (t) + 4 belongs to which category?

A)

Alternating Stresses

B)

Repeated Stresses

C)

Reversed Stresses

D)

None of the above

Correct Answer : Alternating Stresses

Explanation : The mean as well as the amplitude value is non zero hence it belongs to Alternation Stresses category which is the other name of Fluctuation Stresses.

112 .

The stress represented by cos (t) belongs to which category?

A)

Alternating Stresses

B)

Repeated Stresses

C)

Reversed Stresses

D)

Fluctuating Stresses

Correct Answer : Reversed Stresses

Explanation : Half cycle is in tensile stress and other half in compressive stress, hence it belongs to Reversed Stresses Category.

113 .

A power screw is only used to convert rotary motion into linear motion and not for transmitting power.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : False

Explanation : Power screw converts the motion from rotary to linear and is used for power transmission.

114 .

V threads are highly recommended for fastening as well as power transmission purpose.

A)

Yes

B)

Never

C)

In some cases

D)

Canâ€™t be stated

Correct Answer : Never

Explanation : In fastening, high frictional force is required and hence V threads are used whereas in power transmission, reduction in frictional forces is required.

115 .

Which of the following are true for buttress threads?

A)

They are used in vices

B)

Transmit motion in one direction only

C)

Combination of square and trapezoidal threads

D)

All of the above

Correct Answer : All of the above

Explanation : As force is applied only in one direction in a vice so buttress threads are used.

116 .

Tr 40 x 14(P 7), here 14 indicates

A)

Lead

B)

Pitch

C)

Diameter

D)

None of the above

Correct Answer : Lead

Explanation : Tr=Trapezoidal threads,14=Lead(mm),7=Pitch(mm).

117 .

If nominal diameter of screw thread=50mm and pitch=10mm then the mean diameter of the screw thread will be?

A)

40mm

B)

45mm

C)

55mm

D)

60mm

Correct Answer : 45mm

Explanation : Diameter(mean)=Diameter(nominal) – 0.5P .

118 .

Self-locking takes place when

A)

Coefficient of friction is lesser than or equal to the tangent of the helix angle

B)

Coefficient of friction is equal to or greater than the tangent of the helix angle

C)

Coefficient of friction is equal to or greater than the tangent of the helix angle

D)

None of the above

Correct Answer : Coefficient of friction is equal to or greater than the tangent of the helix angle

Explanation : Self locking takes place if load does not descend on its own and that is possible only in c condition.

119 .

If the load itself begin to the screw and descend down, unless a restraining torque is applied then the condition is termed as

A)

Halting

B)

Front driving

C)

Overhaulting

D)

None of the above

Correct Answer : Overhaulting

Explanation : Overhaulting is the condition when load itsel begin to turn the screw.

120 .

Efficiency of the screw depends upon helix angle but does not depend on friction angle.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : False

Explanation : Efficiency=tan(á¼€)/tan(Ç¾+á¼€) where á¼€=Helix angle and Ç¾=Friction angle.

121 .

Efficiency of the screw _______ with increase of coefficient of friction.

A)

decreases

B)

increases

C)

has no effect

D)

cannot be determined

Correct Answer : decreases

Explanation : Efficiency is inversely proportional to tan of the sum of helix and efficiency angle.

122 .

Maximum efficiency of a square threaded is given by

A)

1-sinÇ¾/1+sinÇ¾

B)

1+sinÇ¾/1-sinÇ¾

C)

1-2sinÇ¾/1+2sinÇ¾

D)

1+2sinÇ¾/1-2sinÇ¾

Correct Answer : 1-sinÇ¾/1+sinÇ¾

Explanation : Efficiency=Sin(2á¼€+Ç¾)-Sin Ç¾/Sin(2 á¼€+Ç¾+Sin Ç¾),For max efficiency, sin(2á¼€+ Ç¾)=1.

123 .

Which type of joints is better when the product is subjected to large vibrations: welded or threaded?

A)

Threaded

B)

Welded

C)

Both (A) and (B)

D)

Depends on the magnitude of the vibrational force

Correct Answer : Welded

Explanation : Threaded joints loosen when subjected to vibrations.

124 .

If a fastener is threaded into a tapped hole, then the fastener is likely to be called as

A)

Bolt

B)

Washer

C)

Screw

D)

Screw or bolt

Correct Answer : Screw

Explanation : Bolt is threaded into a nut while screw is threaded into a tapped hole.

125 .

Which of the following is not a function of washer?

A)

Prevents marring of the bolt head and nut surface

B)

Provides bearing surface over large clearance bolts

C)

Distributes load over a large area of clamped parts

D)

Helps in locking of the fastener

Correct Answer : Helps in locking of the fastener

Explanation : Washer doesn’t help in locking of fasteners.

126 .

If there is no place to accommodate the nut, then one would choose the

A)

Studs

B)

Tap Bolts

C)

Through Bolts

D)

None of the above

Correct Answer : Tap Bolts

Explanation : Tap bolts are directly threaded into the clamped parts and does not require any nut.

127 .

If friction angle is 30â€™ then the maximum efficiency of the screw is

A)

33%

B)

50%

C)

66%

D)

None of the above

Correct Answer : 33%

Explanation : Maximum efficiency=1-sinÇ¾/1+sinÇ¾.

128 .

Maximum possible efficiency of a self-locking screw is

A)

33%

B)

50%

C)

66%

D)

75%

Correct Answer : 50%

Explanation : For self locking screw Ç¾(friction angle)>á¼€ (helix angle), hence efficiency < tanÇ¾/tan(Ç¾+á¼€) or efficiency < tanÇ¾(1-tan²Ç¾)/2tanÇ¾.

129 .

In trapezoidal threads, f (coefficient of friction) can be taken as

A)

f sin Î¸

B)

f cos Î¸

C)

f sec Î¸

D)

f cosec Î¸

Correct Answer : f sec Î¸

Explanation : The normal force acting on the thread is W sec θ therefore the effect of the thread angle is to increase the frictional force by a term sec θ.

130 .

If the lateral force acting on the set screw is large and tends to displace one part with respect to other than which point is recommended?

A)

Cut Point

B)

Cone Point

C)

Window Point

D)

Dog Point

Correct Answer : Dog Point

Explanation : Dog point is used when the lateral force is large provided the part has sufficient thickness to accommodate a cylindrical hole for dog point.

131 .

Which of the following requires more space for the rotation of spanner?

A)

Square Head

B)

Hexagonal Head

C)

Cannot be stated

D)

Both require equal space of rotation

Correct Answer : Square Head

Explanation : Angle of rotation for hexagonal head is one sixth of a revolution to enable the next pair of flats to be engaged while it is one fourth of a revolution in case of square head.

132 .

Set screws are subjected to tensile forces only.

A)

Yes

B)

No, they are subjected to compressive forces only

C)

Canâ€™t be determined

D)

Both compressive and tensile

Correct Answer : No, they are subjected to compressive forces only

Explanation : Set screws are subjected to compressive forces only.

133 .

Find the torque required to raise the load of 15kN and mean diameter of triple threaded screw being 46mm. Also given pitch=8mm and coefficient of friction is 0.15.

A)

11831.06N-mm

B)

11813.06N-mm

C)

12811.06N-mm

D)

None of the above

Correct Answer : 11831.06N-mm

Explaination : taná¼€=l/πd or á¼€=9.429’ as l=3p. tan Ç¾=0.15 or Ç¾=8.531’. M=W x d x tan (Ç¾+á¼€)/2.

134 .

What is the collar friction torque if outer and inner diameters are 100mm and 65mm respectively. Coefficient of friction is 0.15 and the load acting is of 15kN. Consider uniform wear theory.

A)

38796.5N-mm

B)

92812.5N-mm

C)

87645.5N-mm

D)

89886.6N-mm

Correct Answer : 92812.5N-mm

Explaination : M=0.15 x W(D+d)/4.

135 .

For a double threaded screw, what will be the tangent of helix angle if nominal diameter and pitch are 100mm and 12mm respectively?

A)

0.023

B)

0.045

C)

0.081

D)

0.094

Correct Answer : 0.081

Explanation : tan á¼€= l/πd where l=2p, d=D-0.5p.

136 .

How many types of jacks are there which can be used in a screw jack?

A)

2

B)

3

C)

4

D)

5

Correct Answer : 2

Explanation : Hydraulic jack and mechanical jack.

137 .

Which of the following does not form the important part of the screw jack?

A)

Cup

B)

Nut

C)

Frame

D)

Coupling

Correct Answer : Coupling

Explanation : There is no specific requirement of coupling in the screw jack.

138 .

The transverse shear stress at the root of the threads in the nut can be given by?(symbols have their usual meaning, z=number of threads in nut)

A)

4W/Ï€tdÂ²

B)

W/Ï€dtz

C)

4W/Ï€dzÂ²

D)

None of the above

Correct Answer : W/Ï€dtz

Explanation : At root of threads, the area parallel to direction of force is considered which is equal to circumference x thickness x no. of threads.

139 .

In which case is the wear more?

A)

Cannot be determined

B)

Equal in both the cases

C)

Conventional power screw

D)

Recirculating power screw

Correct Answer : Conventional power screw

Explanation : In recirculating ball screw, there is a lubricant film between the contacting surfaces and hence lesser wear.

140 .

If for a trapezoidal thread, angle of thread is 15â€™ then what will be the replacement of the coefficient of friction which is 0.15.

A)

0.1335

B)

0.1776

C)

0.1553

D)

0.1667

Correct Answer : 0.1553

Explanation : f=0.15 x sec 15’

141 .

What will be efficiency of the screw in case of raising the load when coefficient of friction is 0.1553 and tangent of helix angle is 0.0813?

A)

34%

B)

43%

C)

45%

D)

54%

Correct Answer : 34%

Explanation : Efficiency= taná¼€(1-0.1553 x tan á¼€)/(0.1553+taná¼€).

142 .

A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the screw torque in terms of clamping force W if nominal diameter=22mm and pitch=5mm.

A)

3.564W N-mm

B)

2.286W N-mm

C)

3.567W N-mm

D)

None of the above

Correct Answer : 2.286W N-mm

Explaination : Mâ‚=Wd x tan(Ç¾+á¼€)/2 or Mâ‚=W x (22-0.5×2.5)x tan(4.66’+8.531’)/2 as tan(á¼€)=l/πd and tanÇ¾=0.15.

143 .

A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the collar torque in terms of clamping force W assuming uniform wear theory if nominal diameter=22mm and pitch=5mm.

A)

3.37W

B)

4.5W

C)

4.25W

D)

5.4W

Correct Answer : 4.25W

Explaination : Mâ‚‚=0.17 x W x (55+45)/4 or Mâ‚‚=4.25W N-mm.

144 .

The nominal diameter of the screw is 22mm and the allowable bearing pressure for the nut is 15N//mmÂ². Find the length of the nut if pitch of the screw is

A)

30mm

B)

25mm

C)

20mm

D)

15mm

Correct Answer : 15mm

Explanation : z=4W/π S(dâ‚²-dâ‚‚²) where S=15N/mm²,dâ‚=22mm and dâ‚‚=17mm. Hencez=2.2 or z=3. Length of nut=zp or l=3 x 5= 15mm.

145 .

If bending stress in a screw is of magnitude 95N/mmÂ² and torsional shear stress of magnitude 15N/mmÂ², then what is the principal shear stress?

A)

48.7N/mmÂ²

B)

49.8 N/mmÂ²

C)

51.4 N/mmÂ²

D)

54.3 N/mmÂ²

Correct Answer : 49.8 N/mmÂ²

Explanation : τ(max)=√(95/2)²+15².

146 .

A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the clamping force W if nominal diameter=22mm and pitch=5mm.

A)

2868.73N

B)

2134.34N

C)

3657.56N

D)

4539.45N

Correct Answer : 2868.73N

Explaination : Net torque=Mâ‚+Mâ‚‚ or 125 x 150=2.286W + 4.25W or W=2868.73N.

147 .

A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the overall efficiency if nominal diameter=22mm and pitch=5mm.

A)

23.21%

B)

21.23%

C)

18.12%

D)

12.18%

Correct Answer : 12.18%

Explaination : Efficiency= W l/2π(Mâ‚+Mâ‚‚) where
Mâ‚=2.286W [Mâ‚=Wd x tan (Ç¾+á¼€)/2 or Mâ‚=W x (22-0.5×2.5) x tan (4.66’+8.531’)/2 as tan(á¼€)=l/πd and tan Ç¾=0.15].
Mâ‚‚=4.25W [Mâ‚‚=0.17 x W x (55+45)/4 or Mâ‚‚=4.25W N-mm],
l=5mm,
W=2868.73N [Net torque=Mâ‚+Mâ‚‚ or 125 x 150=2.286W + 4.25W or W=2868.73N].

148 .

Find the bending stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN acts on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.It is assumed operator exerts a force of 250N at the handle of length 275mm.

A)

123.45N/mm²

B)

124.45N/mm²

C)

132.54N/mm²

D)

142.54N/mm²

Correct Answer : 142.54N/mm²

Explaination : Bending stress=32M/πdáµŒ where M=250 x 275N-mm,d=22-2 x 0.5 x 5mm.

149 .

Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.

A)

25.45N/mm²

B)

21.29N/mm²

C)

31.21N/mm²

D)

35.65N/mm²

Correct Answer : 21.29N/mm²

Explaination : =16M/πdâ‚‚áµŒ where M=Wdâ‚ tan (Ç¾+á¼€)/2 where dâ‚=22-0.5 x 5,W=5000N,
taná¼€=2 x 5/[πx19.5] and dâ‚‚=19.5-0.5 x 5.

150 .

What is the output from differential screws when pitch of the two screws is 12mm and 8mm? Also the nut is rotated by applying a force of 120N at a radius of 300mm and the two screws remain stationary. The torque of raising and lowering for the two screws is 5k N-mm and 2.5k N-mm where k is the effective axial weight on the screw.

A)

13200 N-mm

B)

15200 N-mm

C)

17200 N-mm

D)

19200 N-mm

Correct Answer : 19200 N-mm

Explaination : 120 x 300=5k+2.5k or k=4800N. Output=k x (12-8) or output=19200N-mm.

151 .

What is the efficiency of differential screws when pitch of the two screws is 12mm and 8mm? The nut is rotated by applying a force of 120N at a radius of 300mm and the two screws remain stationary. The torque of raising and lowering for the two screws is 5k N-mm and 2.5k N-mm where k is the effective axial weight on the screw.

A)

6.48%

B)

8.48%

C)

23.1%

D)

42.8%

Correct Answer : 8.48%

Explaination : 120 x 300=5k+2.5k or k=4800N. Output=k x (12-8) or output=19200N-mm. Efficiency=output/2πx120x300.

152 .

Resilience is defined as the property of material to absorb energy when deformed _________ and to release this energy when unloaded.

A)

Elastically

B)

Plastically

C)

Up to fracture point

D)

None of the above

Correct Answer : Elastically

Explanation : It is the definition of resilience.

153 .

If core diameter of bolt is 13.8cm the itâ€™s nominal diameter is given by?

A)

14.67mm

B)

15.34mm

C)

16.34mm

D)

17.27mm

Correct Answer : 17.27mm

Explanation : D=d/0.8.

154 .

The shock absorbing capacity of bolts can be increased by

A)

Increasing the shank diameter

B)

Decreasing the length of shank portion of bolt

C)

Increase the shank diameter and decreasing the length of shank

D)

None of the above

Correct Answer : None of the above

Explanation : Shock absorbing capacity can be increased by decreasing the shank diameter or increasing the length of shank.

155 .

If the length of the shank is doubled, then strain energy absorbed by shank

A)

Become half

B)

Remains same

C)

Doubles

D)

Increases 4 time

Correct Answer : Doubles

Explanation : Strain energy absorbed by shank is linearly proportional to its length.

156 .

Which of the following help in accomplishing the locking?

A)

By plastic deformation

B)

Creating supplementary friction

C)

Using special locking devices like split pins

D)

All of the above

Correct Answer : All of the above

Explanation : All the methods can be employed to lock the screw.

157 .

Which type of threads is recommended for fluctuating loads?

A)

Coarse Threads

B)

Fine threads

C)

Either of fine or coarse

D)

None of the above

Correct Answer : Fine threads

Explanation : Fine threads have lesser helix angle and hence greater resistance for unscrewing and thus are recommended for fluctuating loads.

158 .

Coarse threads have helix angle _____ fine threads.

A)

Lesser than

B)

Equal to

C)

Greater than

D)

There is no relation

Correct Answer : Lesser than

Explanation : Finer threads have lower helix angle.

159 .

Which threads have greater resistance to unscrewing?

A)

Fine

B)

Coarse

C)

They have equal resistance

D)

Cannot be determined

Correct Answer : Fine

Explanation : Fine threads have greater resistance to unscrewing as a result of lower helix angle.

160 .

A flange of radius 200mm is fastened to the machine screw by means of four cap screws of pitch circle radius 150mm. The external force P is 20kN which is loaded at 160mm from the machine screw. There are two dowel pins to take shear load. Determine the maximum effective tensile force acting on the bolt. The four bolts are equally spaced radially.

A)

4777.6N

B)

5777.6N

C)

6777.6N

D)

7777.7N

Correct Answer : 4777.6N

Explaination : Maximum force F=2Pl[a+bCos(90/2)] / 4(2a²+b²).

161 .

All welding processes require pressure along with heat.

A)

Yes

B)

No, fusion doesnâ€™t require

C)

Canâ€™t be stated

D)

None of the above

Correct Answer : No, fusion doesnâ€™t require

Explanation : Welding processes involving only heat and no pressure are called the fusion welding processes.

162 .

Rails in the field are generally welded by using

A)

Gas welding

B)

Forge welding

C)

Thermit welding

D)

Electric arc welding

Correct Answer : Thermit welding

Explanation : Wherever it is uneconomical to carry welding equipments, thermit welding is used.

163 .

In gas welding which of the following is generally used?

A)

Oxygen-Hydrogen

B)

Oxygen-Acetylene

C)

Oxygen-Hydrogen or Oxygen-Acetylene

D)

None of the above

Correct Answer : Oxygen-Hydrogen or Oxygen-Acetylene

Explanation : Intense heat is released I a controlled way and at a moderate temperature.

164 .

Which of the following rivet head consist of frustum of cone attached to the shank?

A)

Cone head rivet

B)

Pan head rivet

C)

Flat head rivet

D)

Countersunk head rivet

Correct Answer : Cone head rivet

Explanation : Cone head rivet consist of frustum of cone attached to shank.

165 .

Among flat head and snap head rivet, which has the higher head height?

A)

Flat

B)

Snap

C)

Equal

D)

None of the above

Correct Answer : Snap

Explanation : Flat head has lesser height of protruding head and thus it does not weaken the plates being assembled.

166 .

Which of the following are used in light sheet metal work?

A)

Snap head rivets

B)

Button head rivets

C)

Each of the mentioned

D)

Tinmenâ€™s rivets

Correct Answer : Tinmenâ€™s rivets

Explanation : Tinmen’s rivets are flat head rivets of small sizes.

167 .

If force act in a direction parallel to the direction of weld, then fillet weld is called as?

A)

Parallel

B)

Transverse

C)

Longitudinal

D)

Longitudinal or Parallel

Correct Answer : Longitudinal or Parallel

Explanation : Parallel fillet weld consist of force acting in a direction of weld.

168 .

The length of each of the two equal sides of a parallel fillet weld is called

A)

Arm

B)

Throat

C)

Leg

D)

None of the above

Correct Answer : Leg

Explanation : Leg is the length of each of the two equal sides of a parallel fillet weld.

169 .

Relation between throat and leg for a parallel fillet weld is

A)

t =h Cos (45â€™)

B)

h= t

C)

h =t Cos (45â€™)

D)

None of the above

Correct Answer : t =h Cos (45â€™)

Explanation : Throat is the minimum cross section of the weld and that plane lies at 45’ for a parallel fillet weld.

170 .

Among gas and electric arc welding, which has the higher rate of heating?

A)

Gas welding

B)

Electric arc welding

C)

Gas welding and electric arc welding have equal rate of heating

D)

None of the above

Correct Answer : Electric arc welding

Explanation : Gas welding has a gas temperature of about 3200’C while arc temperature is about 40000’C.

171 .

Forge welding involves heating of parts to elastic stage and joint is prepared by impact force.

A)

Yes

B)

No, it is done up to plastic stage

C)

Heating is done up to boiling point

D)

None of the above

Correct Answer : No, it is done up to plastic stage

172 .

Hard peening is_______.

A)

Hammering the weld across the length while the joint is hot

B)

Hammering the weld along the length while the joint is cold

C)

Hammering the weld across the length while the joint is cold

D)

Hammering the weld along the length while the joint is hot

Correct Answer : Hammering the weld along the length while the joint is hot

173 .

Which type of welding is generally used in automobile sector?

A)

Gas welding

B)

Forge welding

C)

Electric resistance welding

D)

Electric arc welding

Correct Answer : Electric resistance welding

Explanation : Electric resistance welding can be easily automated and hence is used in automobile sector.

174 .

Two plates each of thickness t are to be riveted together. If length of shank portion necessary to form the closing head is a, then length of rivet shank is given by?

A)

2t+a

B)

t+2a

C)

2(t+a)

D)

None of the above

Correct Answer : 2t+a

175 .

What is the other name for pitch?

A)

Row pitch

B)

Back pitch

C)

Transverse pitch

D)

None of the above

Correct Answer : None of the above

Explanation : Transverse, back and row pitch are all same. It is the distance b/w two consecutive rows of pitch.

176 .

Failure in rivet occurs by which mode?

A)

Tensile

B)

Shear

C)

Compression

D)

Each of the mentioned

Correct Answer : Each of the mentioned

Explanation : Rivet may fail by shearing, plates between two rivets can undergo tensile failure and plates might fail by crushing.

177 .

Calculate the diameter of the rivets by shear considerations if permissible shear stress in rivets is 60N/mmÂ² and P=15kN.

A)

9mm

B)

8mm

C)

7mm

D)

6mm

Correct Answer : 9mm

Explanation : P=4x[τ x πd²/4].

178 .

Calculate the diameter of the rivets by crushing consideration if permissible compression stress in rivets is 120N/mmÂ², thickness of plate 3mm and P=15kN.

A)

11.5mm

B)

10.4mm

C)

9.2mm

D)

8.6mm

Correct Answer : 10.4mm

Explanation : P=4x[d t σ].

179 .

Calculate width of the band if permissible tensile stress is 80N/mmÂ². Force P=15kN and diameter of the rivet can be taken as 9mm. Given thickness=3mm

A)

54.6mm

B)

76.66mm

C)

80.5mm

D)

79.5mm

Correct Answer : 80.5mm

Explanation : [w-2d]tσ=P.

180 .

The two plates are welded as shown below figure. It is an example of

A)

Parallel fillet weld

B)

Transverse fillet weld

C)

Parallel as well as transverse fillet weld

D)

None of the above

Correct Answer : Parallel as well as transverse fillet weld

Explaination : In two welds force acts parallel as well as perpendicular to the direction of weld.

181 .

A bracket is shown welded to a vertical column by means of two fillet welds. The bending stress induced in the welds can be given by

A)

My/I

B)

My/2I

C)

2My/I

D)

None of the above

Correct Answer : My/I

182 .

Calculate the moment of inertia about the axis parallel to welds and shift it to CG by considering thickness of welds t.

A)

125000 t

B)

250000 t

C)

táµŒ+2000t

D)

None of the above

Correct Answer : 250000 t

Explanation : I=[50táµŒ/12 + (50t)x50² ] x 2, ignoring táµŒ term.

183 .

Find the bending stress in the top weld is if thickness of weld is t. Given P=15kN and e=120mm.

A)

200/t

B)

230/t

C)

360/t

D)

None of the above

Correct Answer : 360/t

Explanation : σ=My/I or M=15000×120, y=50 and I=250000t.

184 .

If a circular shaft is welded to the plate by means of circumferential fillet, then the shaft is subjected to torsional moment M. If throat of weld is t, then torsional shear stress is given by

A)

M/Ï€trÂ²

B)

M/4Ï€trÂ²

C)

Both (A) and (B)

D)

M/2Ï€trÂ²

Correct Answer : M/2Ï€trÂ²

Explanation : Stress=Mr/J, here J=2πtráµŒ[I(xx)+I(yy)].

185 .

The bracket welded to the vertical plate by means of two fillet welds. Calculate size of the welds if P=40kN, leg=4mm and e=400mm. Maximum permissible value of shear stress in the weld is 70N/mm².

A)

2.1mm

B)

1.7mm

C)

1.4mm

D)

3mm

Correct Answer : 2.1mm

Explaination : σ=My/I where y=250mm,I=2xtx500áµŒ/12 and τâ‚=P/2xtx500.τ=√σ²+τâ‚² or 104/t=70 and h=t/0.707.

186 .

Which of the following isn't a main part of rivet?

A)

Shank

B)

Point

C)

Head

D)

Thread

Correct Answer : Thread

Explanation : There aren’t any threads in rivets.

187 .

A rivet is specified as a 20mm rivet. What does it mean?

A)

Shank dia 20mm

B)

Head dia 20mm

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Shank dia 20mm

188 .

The amount by which the two rods to be joined are drawn together is called as?

A)

Lead

B)

Draw

C)

Pitch

D)

Portray

Correct Answer : Draw

Explanation : Draw measures the amount of distance advancing after which spigot rests on socket.

189 .

Among punching and drilling, which is cheaper?

A)

Drilling

B)

Equally expensive

C)

Punching

D)

Cannot be determined

Correct Answer : Punching

Explanation : Drilling has more accuracy and is more expensive.

190 .

The shaft is always stepped with ________ diameter at the middle portion and __________ diameter at the shaft ends.

A)

Zero, infinity

B)

Minimum, minimum

C)

Maximum, minimum

D)

Minimum, maximum

Correct Answer : Maximum, minimum

Explanation : Maximum diameter is in the middle portion while it is minimum at the ends.

191 .

_____ is used for a shaft that supports rotating elements like wheels, drums or rope sleaves.

A)

Shaf

B)

Axle

C)

Spindle

D)

None of the above

Correct Answer : Spindle

192 .

Is it necessary for an axle to be ______ with respect to rotating element?

A)

Moving

B)

Moving or stationary

C)

Stationary

D)

None of the above

Correct Answer : Moving or stationary

Explanation : The axle may be stationary or rotate with the element.

193 .

Shafts are subjected to ______ forces.

A)

Tensile

B)

Shear

C)

Compressive

D)

None of the above

Correct Answer : Tensile

Explanation : Shafts are subjected to tensile forces.

194 .

When the shaft is subjected to pure torsional moment, the torsional stress is given by?

A)

8M/Ï€dáµŒ

B)

16M/Ï€dáµŒ

C)

32M/Ï€dáµŒ

D)

None of the above

Correct Answer : 16M/Ï€dáµŒ

Explanation : Stress=Mr/J where r=d/2 and J=πdâ´/64.

195 .

When the shaft is subjected to pure bending moment, the bending stress is given by?

A)

8M/Ï€dáµŒ

B)

16M/Ï€dáµŒ

C)

32M/Ï€dáµŒ

D)

None of the above

Correct Answer : 32M/Ï€dáµŒ

Explanation : Stress =My/I where y=d/2 and I=πdâ´/64.

196 .

In distortion energy theorem, if a unit cube is subjected to biaxial stress, then S(yt) is given by which of the following?

A)

Ïƒâ‚Â²+ Ïƒâ‚Ïƒâ‚‚ +Ïƒâ‚‚Â²

B)

Ïƒâ‚Â²- Ïƒâ‚Ïƒâ‚‚ +Ïƒâ‚‚Â²

C)

âˆš (Ïƒâ‚Â²+ Ïƒâ‚Ïƒâ‚‚ +Ïƒâ‚‚Â²)

D)

âˆš (Ïƒâ‚Â²- Ïƒâ‚Ïƒâ‚‚ +Ïƒâ‚‚Â²)

Correct Answer : âˆš (Ïƒâ‚Â²- Ïƒâ‚Ïƒâ‚‚ +Ïƒâ‚‚Â²)

Explanation : S(yt)=√[(σâ‚ -σâ‚‚)²+(σâ‚‚ -σâ‚ƒ)²+(σâ‚ƒ -σâ‚)²]/2, for σâ‚ƒ=0; expression a is obtained.

197 .

A muff coupling is connecting two shafts. The torque involved is 650N-m. The shaft diameter is 45mm with length and breadth of the key being 14mm and 80mm respectively. Find the shear stress induced in the key.

A)

25.8N/mm²

B)

30.2N/mm²

C)

34.4N/mm²

D)

None of the above

Correct Answer : 25.8N/mm²

Explaination : τ =2M/dbl.

198 .

The region of safety for biaxial stresses is of which shape in the case of maximum distortion energy theorem.

A)

Circle

B)

Square

C)

Ellipse

D)

Rectangle

Correct Answer : Ellipse

Explanation : S(yt)= √ (σâ‚²- σâ‚σâ‚‚ +σâ‚‚²) or S²(yt)= (σâ‚²- σâ‚σâ‚‚ +σâ‚‚²). This is an equation of ellipse.

199 .

A muff coupling is connecting two shafts. The torque involved is 650N-m. The shaft diameter is 45mm with length and height of the key being 14mm and 80mm respectively. Find the compressive stress induced in the key.

A)

45.5N/mm²

B)

51.6N/mm²

C)

70.1 N/mm²

D)

None of the above

Correct Answer : 51.6N/mm²

Explaination : σ=4M/dhl

200 .

Among maximum shear stress theory and distortion energy theory, which gives the higher value shear yield strength?

A)

Distortion energy theory

B)

Maximum shear stress theory

C)

Both give equal values

D)

Vary from material to material

Correct Answer : Distortion energy theory

Explanation : Maximum shear stress theory gives S(sy)=0.5S(yt) while Distortion energy theorem gives S(sy)=0.577(Syt).

201 .

While designing shaft on the basis of torsional rigidity, angle of twist is given by?

A)

Ml/Gdâ´

B)

584Ml/Gdâ´

C)

292 Ml/Gdâ´

D)

None of the above

Correct Answer : 584Ml/Gdâ´

Explanation : θ=(180/π)xMl/GJ where J=πdâ´/32.

202 .

According to the ASME code, maximum allowable shear stress is taken as X% of yield strength or Y% of ultimate strength.

A)

X=30 Y=18

B)

X=18 Y=18

C)

X=18 Y=30

D)

X=30 Y=30

Correct Answer : X=30 Y=18

Explanation : ASME Standard. The lesser value is taken among the two.

203 .

The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm. Calculate the tension in the rope of pulley C.

A)

6778.3N and 7765.3N

B)

5468.4N ad 8678.3N

C)

5948.15N and 2288.75N

D)

None of the above

Correct Answer : 5948.15N and 2288.75N

Explaination : (Pâ‚ƒ-Pâ‚„)x150=549.3×1000 and Pâ‚ƒ/Pâ‚„=2.6. Hence Pâ‚ƒ=5948.15N and Pâ‚„=2288.75N.

204 .

If yielding strength=400N/mmÂ², the find the permissible shear stress according to ASME standards.

A)

422 N/mmÂ²

B)

268 N/mmÂ²

C)

76 N/mmÂ²

D)

72 N/mmÂ²

Correct Answer : 72 N/mmÂ²

205 .

Calculate the shaft diameter on rigidity basis if torsional moment is 196000N-mm, length of shaft is 1000mm. Permissible angle of twist per meter is 0.5â€™ and take G=79300N/mmÂ².

A)

41.2mm

B)

38.8mm

C)

35.8mm

D)

None of the above

Correct Answer : 41.2mm

Explanation : dâ´=584Ml/Gθ.

206 .

A force 2P is acting on the double transverse fillet weld. Leg of weld is h and length l. Determine the shear stress in a plane inclined at Î¸ with horizontal.

A)

P(SinÎ¸+CosÎ¸)/hl

B)

PcosÎ¸(SinÎ¸+CosÎ¸)/hl

C)

PSinÎ¸(SinÎ¸+CosÎ¸)/hl

D)

None of the above

Correct Answer : PSinÎ¸(SinÎ¸+CosÎ¸)/hl

Explanation : F=PSinθ and width=h/(Sinθ+Cosθ)

207 .

Maximum shear stress in transverse fillet weld of leg h and length l is

A)

P/hl

B)

1.21P/hl

C)

P/1.21hl

D)

None of the above

Correct Answer : 1.21P/hl

Explanation : τ= PSinθ(Sinθ+Cosθ)/hl, by maximising it θ=67.5’ and hence find corresponding τ.

208 .

A sunk key fits in the keyway of the _____ only.

A)

Hub

B)

Sleeve

C)

Both (A) and (B)

D)

Neither hub nor sleeve

Correct Answer : Hub

Explanation : Sunk key fits halfway in the hub and halfway in the shaft.

209 .

Woodruff key permits _____ movement b/w shaft and the hub.

A)

Axial

B)

Radial

C)

Eccentric

D)

None of the above

Correct Answer : Radial

Explanation : Woodruff key is a sunk key and doesn’t permit axial moment.

210 .

Involute splines have stub teeth with a pressure angle of ___

A)

10

B)

30

C)

45

D)

None of the above

Correct Answer : 45

Explanation : Pressure angle is 30’ and not 60’.

211 .

Determine the length of kennedy key required to transmit 1200N-m and allowable shear in the key is 40N/mm². The diameter of shaft and width of key can be taken as 40mm and 10mm respectively.

A)

36mm

B)

46mm

C)

49mm

D)

53mm

Correct Answer : 53mm

Explaination : l=M/[dbτ√2]

212 .

If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling.

A)

60mm

B)

80mm

C)

100mm

D)

None of the above

Correct Answer : 100mm

Explanation : Dia=2.5d.

213 .

If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling.

A)

140mm

B)

120mm

C)

100mm

D)

80mm

Correct Answer : 140mm

Explanation : L=3.5d.

214 .

Calculate the force acting on the each pin in flexible coupling if torque transmitted is 397N-m and PCD=120mm with number of pins 6.

A)

1102.8N

B)

1320.3N

C)

1400.3N

D)

None of the above

Correct Answer : 1102.8N

215 .

If shaft diameter is 30mm and number of pins emplaced are 6, then the diameter of the pin will be?

A)

5.4mm

B)

5.6mm

C)

5.9mm

D)

6.1mm

Correct Answer : 6.1mm

Explanation : dâ‚=.5d/√N.

216 .

Find the shear stress in a flange at the junction of hub in rigid flanged coupling if torsional moment is 2980N-m and diameter of hub being 125mm. Also the thickness of flange is 25mm.

A)

4.22N/mmÂ²

B)

4.84N/mmÂ²

C)

6.77N/mmÂ²

D)

10.24N/mmÂ²

Correct Answer : 4.84N/mmÂ²

Explanation : τ=2M/πd²t.

217 .

Determine the diameter of the bolts used in rigid flange coupling if transmitted torque is 270N-m, pitch circle diameter=125mm and four bolts are emplace in the coupling. Permissible shear stress in the bolts is 70N/mm².

A)

3.6mm

B)

3.8mm

C)

4.0mm

D)

4.4mm

Correct Answer : 4.4mm

Explaination : d²=8M/πDNτ

218 .

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m.

A)

41666.7N

B)

45968.3N

C)

51234.4N

D)

None of the above

Correct Answer : 41666.7N

Explaination : P=2M/fdn

219 .

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm².

A)

21mm

B)

23mm

C)

25mm

D)

27mm

Correct Answer : 27mm

Explaination : Ax80=2M/fdn.

220 .

If shaft diameter is 60mm, how many bolts are recommended for rigid flange coupling?

A)

2

B)

3

C)

4

D)

5

Correct Answer : 4

Explanation : If shaft diameter is between 40mm and 100mm, 4 bolts are used.

221 .

Which of the following function can the spring perform?

A)

Absorb shock

B)

Store energy

C)

Measure force

D)

All of the above

Correct Answer : All of the above

Explanation : Spring can easily perform all the listed functions.

222 .

The longest leaf in a leaf spring is called centre leaf.

A)

Yes

B)

It is called middle leaf

C)

It is called master leaf

D)

None of the above

Correct Answer : It is called master leaf

Explanation : It is called master leaf.

223 .

If spring index=2.5, what can be concluded about stresses in the wire?

A)

They are high

B)

They are moderate

C)

They are negligible

D)

Cannot be determined

Correct Answer : They are high

Explanation : If indexis <3 then stresses are high due to curvature effect.

224 .

If the spring is compressed completely and the adjacent coils touch each other,the the length of spring is called as?

A)

Free length

B)

Solid length

C)

Compressed length

D)

None of the above

Correct Answer : Solid length

225 .

Active and inactive, both types of coils support the load although both donâ€™t participate in spring action.

A)

Inactive coils donâ€™t support the load

B)

Active coils donâ€™t support the load

C)

Both active and inactive support the load

D)

Both active and inactive donâ€™t support the load

Correct Answer : Inactive coils donâ€™t support the load

226 .

If uncompressed length of spring is 40mm and number of coils 10mm, then pitch of coil is?

A)

2

B)

4

C)

40/9

D)

40/11

Correct Answer : 40/9

Explanation : Pitch=Uncompressed length/N-1.

227 .

If number of coils are 8 and wire diameter of spring 3mm, then solid length is given by?

A)

21mm

B)

24mm

C)

27mm

D)

None of the above

Correct Answer : 24mm

228 .

A concentric spring consists of 2 sprigs of diameter 10mm and 4mm. The net force acting on the composite spring is 5000N. Find the force acting on each of the two springs.

A)

645.3N and 4354.7N

B)

786.4N and 4213.6N

C)

1232.2N and 3767.8N

D)

689.7N and 4310.3N

Correct Answer : 689.7N and 4310.3N

Explaination : Pâ‚/Pâ‚‚=dâ‚²/dâ‚‚² and Pâ‚+Pâ‚‚=5000.

229 .

Angle of rotation o arbour with respect to drum is given by?

A)

8 ML/EbtáµŒ

B)

12ML/EbtáµŒ

C)

16ML/EbtáµŒ

D)

None of the above

Correct Answer : 12ML/EbtáµŒ

Explanation : θ=ML/EI where I=btáµŒ/12.

230 .

Calculate the bending stress induced in the strip of the helical spring. The spring is subjected to a moment of 1250N-mm with breadth and thickens of the strip being 11mm and 1.5mmm respectively.

A)

508.8N/mm²

B)

564.3N/mm²

C)

597.3N/mm²

D)

606.1N/mm²

Correct Answer : 606.1N/mm²

231 .

Two spring having stiffness constants of 22N/mm and 25N/mm are connected in parallel. They are to be replaced by a single spring to have same effect. The stiffness of that spring will be?

A)

3N/mm

B)

11.7N/mm

C)

47N/mm

D)

None of the above

Correct Answer : 47N/mm

Explaination : k=22+25

232 .

If the spring have same solid length and number of coils in the two springs are 8 and 10, then find the diameter of the spring with 8 coils. It is given diameter of spring with 10 coils is 12mm.

A)

9mm

B)

9.6mm

C)

12mm

D)

15mm

Correct Answer : 9mm

Explaination : Nâ‚dâ‚=Nâ‚‚dâ‚‚

233 .

For a helical torsion sprig, the stress concentration factor at inner fibre is? Give spring index=5.

A)

1.005

B)

1.175

C)

1.223

D)

1.545

Correct Answer : 1.005

Explanation : K=4C²-C-1/4C(C-1).

234 .

For a helical torsion sprig, the stress concentration factor at outer fibre is? Give spring index=5.

A)

0.78

B)

0.87

C)

1.87

D)

2.71

Correct Answer : 0.87

Explanation : K=4C²+C-1/4C(C+1)

235 .

If a spring has plain ends then number of inactive coils is?

A)

0

B)

1

C)

2

D)

3

Correct Answer : 0

Explanation : There are no inactive coils in plain ends.

236 .

The angle of twist for the equivalent bar to a spring is given by? (Symbols have their usual meaning)

A)

16PDN/GdáµŒ

B)

16PDÂ²N/Gdâ´

C)

8PDN/GdáµŒ

D)

8PDÂ²N/Gdâ´

Correct Answer : 16PDÂ²N/Gdâ´

Explanation : θ=Ml/GJ where M=PD/2, l=πDN and J=πdâ´/32

237 .

The axial deflection of spring for the small angle of Î¸ is given by?

A)

328PDáµŒN/Gdâ´

B)

16PDáµŒN/Gdâ´

C)

8PDáµŒN/Gdâ´

D)

8PDÂ²N/GdáµŒ

Correct Answer : 8PDáµŒN/Gdâ´

Explanation : Deflection=θxD/2

238 .

A railway wagon moving with a speed of 1.5m/s is brought to rest by bumper consisting of two springs. Mass of wagon is 100kg. The springs are compressed by 125mm. Calculate the maximum force acting on each spring.

A)

1200N

B)

1400N

C)

1500N

D)

1800N

Correct Answer : 1800N

Explaination : mv²/2=Pxdeflection/2

239 .

Find total number coils in a spring having square and ground ends. Deflection in the spring is 6mm when load of 1100N is applied. Modulus of rigidity is 81370N/mm². Wire diameter and pitch circle diameter are 10mm and 50mm respectively.

A)

4

B)

5

C)

6

D)

7

Correct Answer : 7

Explaination : Deflection=8PDáµŒN/Gdâ´ or N=4.4 or 5. Total coils=5+2(square grounded ends).

240 .

Find the Wahl's factor if spring index is 6.

A)

1.2020

B)

1.2424

C)

1.2525

D)

1.5252

Correct Answer : 1.2525

Explanation : K=[4C-1/4C-4]+0.615/C.

241 .

Bending stress in graduated length leaves are more than that in full length leaves.

A)

Yes

B)

No

C)

In some cases

D)

None of the above

Correct Answer : No

Explanation : Bending stress in full length leaves is around 50% higher than graduated length leaves.

242 .

A leaf spring consists of 3 extra full length leaves and 14 graduated length leaves. The maximum force that can act on the spring is 70kN and the distance between eyes of the spring is 1.2m. Width and thickness of the leaves are 100mm and 12mm respectively. If modulus of elasticity is 207000N/mm², calculate the initial nip.

A)

22.5mm

B)

23.1mm

C)

24.9mm

D)

26.8mm

Correct Answer : 24.9mm

Explaination : C=2PLáµŒ/EnbtáµŒ where L=1.2/2, n=3+14,P=70/2.

243 .

A leaf spring consists of 3 extra full length leaves and 14 graduated length leaves. The maximum force that can act on the spring is 70kN and the distance between eyes of the spring is 1.2m. Width and thickness of the leaves are 100mm and 12mm respectively. Calculate the initial pre load required to close the nip.

A)

4332.2N

B)

4674.1N

C)

4985.4N

D)

Can’t be determined

Correct Answer : 4674.1N

Explaination : P=2x3x14x35000/17(3×3+2×14).

244 .

Propagation of fatigue failure is always due to compressive stresses.

A)

Due to tensile

B)

Due to fatigue

C)

Due to bending

D)

None of the above

Correct Answer : Due to tensile

Explanation : Propagation is always due to tensile stresses.

245 .

When two Belleville springs are in parallel, half force is obtained for a given deflection.

A)

Half force

B)

Double force

C)

Same force

D)

None of the above

Correct Answer : Double force

246 .

Belleville spring can only produce linear load deflection characteristics.

A)

Only linear

B)

Linear as well as non linear

C)

Non-linear

D)

None of the above

Correct Answer : Linear as well as non linear

Explanation : Beliville spring can provide any linear or non-linear load deflection characteristics.

247 .

Clutch and coupling perform the same action.

A)

Both being permanent joints

B)

Both being temporary joints

C)

No they are different type of joints

D)

None of the above

Correct Answer : No they are different type of joints

Explanation : Clutch is a temporary joint while coupling is a permanent joint.

248 .

In positive contact clutches, power transmission is achieved by means of friction.

A)

Yes

B)

It is achieved by shear contact

C)

Major part is achieved by friction

D)

None of the above

Correct Answer : It is achieved by shear contact

Explanation : Power transmission is achieved by interlocking of jaws or teeth.

249 .

A plate clutch consists of 1 pair of contacting surfaces. The inner and outer diameter of the friction disk is 100mm and 200mm respectively. The coefficient of friction is 0.2 and permissible intensity of pressure is 1.5N/mm². Assuming uniform wear theory, calculate the operating force in the clutch.

A)

12344N

B)

15546N

C)

23562N

D)

24543N

Correct Answer : 23562N

Explaination : P=πpd(D-d)/2

250 .

A plate clutch consists of 1 pair of contacting surfaces. The inner and outer diameter of the friction disk is 100mm and 200mm respectively. The coefficient of friction is 0.2 and permissible intensity of pressure is 1.5N/mm². Assuming uniform wear theory, calculate the torque transmitting capacity of the clutch.

A)

334.53N-m

B)

353.43N-m

C)

398.34N-m

D)

412.23N-m

Correct Answer : 353.43N-m

Explaination : P=πpd(D-d)/2 and M=μP(D+d)/4.

251 .

A plate clutch consists of 1 pair of contacting surfaces. The inner and outer diameter of the friction disk is 100mm and 200mm respectively. The coefficient of friction is 0.2 and permissible intensity of pressure is 1.5N/mm². Assuming uniform wear theory, calculate the power transmitting capacity of the clutch at 80rad/s.

A)

27kW

B)

32kW

C)

39kW

D)

44kW

Correct Answer : 44kW

Explaination : P= πp(D²-d²)/4 and M=μP(DáµŒ-dáµŒ)/3(D²-d²).Power=Mxω.

252 .

Belt, chain and rope are called rigid drives.

A)

True

B)

False

C)

Can not say

D)

Belt is a flexible drive only

Correct Answer : Belt is a flexible drive only

253 .

Is there any worry for overloading conditions in flexible belt drives?

A)

Yes

B)

No

C)

Depends on external factrors

D)

Only after a particular threshold limit

Correct Answer : No

Explanation : In case of overloading, belt slips over the pulley and hence protect it from the overload.

254 .

V belts have v shaped cross section.

A)

No, trapezium

B)

No, circular

C)

No, spherical

D)

No, rectangular

Correct Answer : No, trapezium

Explanation : They have trapezoidal cross section.

255 .

V belts result in smooth and quite operation even at high speeds.

A)

Yes

B)

No they are very noisy

C)

They are not endless and hence not smooth motion

D)

None of the above

Correct Answer : Yes

256 .

A cone clutch consists of inner conical surface and outer cylindrical surface.

A)

Both conical

B)

Both cylindrical

C)

Outer conical and inner cylindrical

D)

None of the above

Correct Answer : Both conical

Explanation : It consists of both inner and outer conical surfaces.

257 .

Power is transmitted only by key and friction in the cone clutch.

A)

By key only

B)

Only by spline

C)

By friction only

D)

By key, spline and friction

Correct Answer : By key, spline and friction

Explanation : Power is transmitted via key, friction and spline.

258 .

The torque transmitting capacity of cone clutch increases as its semi vertical angle increase.

A)

True

B)

Decreases

C)

Remains constant

D)

None of the above

Correct Answer : Decreases

Explanation : Torque transmitted is inversely proportional to the sin of the semi vertical angle.

259 .

Find number of contacting surfaces for a multi disk clutch plate transmitting torque of 10N-m and inner and outer diameters of friction lining are 70mm and 100mm respectively. The operating force is of magnitude 305N and coefficient of friction is 0.2.

A)

2

B)

3

C)

4

D)

5

Correct Answer : 4

Explaination : z=4M/μP(D+d)

260 .

In a centrifugal clutch, when the centrifugal force is slightly more than the spring force, shoe begins to move in a radially inward direction.

A)

Radially inwards

B)

Radially upwards

C)

Radially outwards

D)

Radially downwards

Correct Answer : Radially outwards

Explanation : It moves in radially outward direction.

261 .

A cone clutch transmits 24kW at 490rpm. The coefficient of friction is 0.2 and allowable intensity of pressure is 0.35N/mm². The semi cone angle is 12â°. The outer diameter is fixed as 310mm.Assuming uniform wear theory; find the maximum torque which is transmitted.

A)

454.5N-m

B)

467.72N-m

C)

502.4N-m

D)

542.3N-m

Correct Answer : 467.72N-m

Explaination : M=Powerx10áµŒx60/2πN.

262 .

A cone clutch transmits 24kW at 490rpm. The coefficient of friction is 0.2 and allowable intensity of pressure is 0.35N/mm². The semi cone angle is 12â°. The outer diameter is fixed as 310mm.Assuming uniform wear theory; calculate force required to engage clutch.

A)

2231.5N

B)

3241.5N

C)

3546.9N

D)

4354.5N

Correct Answer : 3241.5N

Explaination : P=4MSiná¼€/μ(D+d)

263 .

A cone clutch transmits 24kW at 490rpm. The coefficient of friction is 0.2 and allowable intensity of pressure is 0.35N/mm². The semi cone angle is 12â°. The outer diameter is fixed as 310mm.Assuming uniform wear theory; find the face width of friction lining.

A)

48.1mm

B)

52.2mm

C)

56.8mm

D)

None of the above

Correct Answer : 48.1mm

264 .

The layer of a belt is generally called as

A)

Layer

B)

Sediment

C)

Ply

D)

Segment

Correct Answer : Ply

265 .

Fabric rubber belts are not widely used as they canâ€™t be operated at high speeds.

A)

They can be used at high velocities

B)

Limiting velocity is 20m/s

C)

They canâ€™t be used at velocities 50m/s

D)

None of the above

Correct Answer : They can be used at high velocities

266 .

A shorter centre distance is always preferred in belt drives.

A)

No due to instability

B)

Yes due to instability

C)

No due to stability

D)

Yes due to stability

Correct Answer : Yes due to stability

267 .

The diameter of the shorter pulley in leather belt drive is 265mm. It is rotating at 1440 rpm. Calculate the velocity of the belt.

A)

20m/s

B)

25m/s

C)

30m/s

D)

None of the above

Correct Answer : 20m/s

Explanation : v=πdn/60×1000

268 .

If velocity ratio is more than 3, then centre distance is given by 2D.

A)

By D

B)

By 3D

C)

By 4D

D)

By 5D

Correct Answer : By D

269 .

The energy absorb by brake is always kinetic.

A)

Potential

B)

Kinetic or potential

C)

No, potential

D)

Strain Energy

Correct Answer : Kinetic or potential

Explanation : It can be either kinetic or potential.

270 .

Pneumatic brakes are same as electrical brakes.

A)

Yes both deals with pressure

B)

Yes both are concerned with electricity

C)

No, one deals with pressure and other with electricity

D)

None of the above

Correct Answer : No, one deals with pressure and other with electricity

Explanation : Pneumatic brakes are operated by fluid pressure.

271 .

A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Calculate energy absorbed by the brake if square of radius of gyration is 0.2.

A)

134.2kJ

B)

134.3kJ

C)

165.3kJ

D)

None of the above

Correct Answer : 134.3kJ

272 .

A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the average angular velocity during braking period.

A)

15.45rad/s

B)

17.32rad/s

C)

18.32rad/s

D)

None of the above

Correct Answer : 18.32rad/s

Explaination : ω(avg)=[ω()initial+ω(final)]/2.

273 .

A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the angle through which disk rotated during braking period.

A)

24.6rad

B)

27.5rad

C)

29.3rad

D)

32.4rad

Correct Answer : 29.3rad

Explaination : ω(avg)=[ω()initial+ω(final)]/2 and θ=ωt.

274 .

A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the torque capacity of the brake.

A)

4583.6N-m

B)

812.4N-m

C)

612.4N-m

D)

None of the above

Correct Answer : 4583.6N-m

275 .

If torque capacity of a block brake is 240N-m and radius of drum is 210mm with coefficient of friction 0.4.

A)

2334.62N

B)

2857.14N

C)

3443.42N

D)

None of the above

Correct Answer : 3443.42N

Explanation : N=M/μR

276 .

If initially drum of radius 200mm is rotating at 100rpm, then calculate the heat generated if frictional force acting is 1140N.

A)

3345W

B)

4456W

C)

4987W

D)

5969W

Correct Answer : 5969W

Explanation : Heat=Frictional forcexaverage velocity.

277 .

A pivoted double block brake has a drum radius of 280mm with two shoes subtending an angle of 100â°. Calculate the distance of pivot from axis of drum.

A)

289.5mm

B)

314.3mm

C)

321.5mm

D)

None of the above

Correct Answer : 314.3mm

Explanation : h=4Rsinθ/2θ+sin2θwhere θ=100/2.

278 .

A pivoted double block brake has a drum radius of 280mm with two shoes subtending an angle of 100â°. Maximum pressure intensity is 0.5N/mm². If the width of friction lining is 90mm, find the reaction at pivot in horizontal direction. Assume coefficient of friction as 0.2.

A)

1720N

B)

2113N

C)

2870N

D)

3440N

Correct Answer : 3440N

Explaination : R(y)=μRwp(2θ+sin2θ)/2

279 .

A pivoted double block brake has a drum radius of 280mm with two shoes subtending an angle of 100â°. Maximum pressure intensity is 0.5N/mm². If the width of friction lining is 90mm, find the reaction at pivot in horizontal direction. Assume coefficient of friction as 0.2.

A)

16789N

B)

17200N

C)

21123N

D)

None of the above

Correct Answer : 17200N

Explaination : R(x)=Rwp(2θ+sin2θ)/2.

280 .

Calculate the angle of wrap if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.

A)

174.8â°

B)

167.8â°

C)

159.3â°

D)

None of the above

Correct Answer : 174.8â°

Explanation : á½°=180 – 2sin¯¹(D-d/2C).

281 .

Calculate the belt length if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.

A)

4.66m

B)

5.26m

C)

6.5m

D)

6.94m

Correct Answer : 6.94m

Explanation : L=2C + π(D+d)/2 + (D-d)²/4C.

282 .

Calculate the arc of contact if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.

A)

1.01

B)

1.02

C)

1.03

D)

1.04

Correct Answer : 1.02

Explanation : á½°=180 – 2sin¯¹(D-d/2C). Factor=1+ (1.04-1)(180-174.8)/(180-170).

283 .

If tensions in the belt are Pâ‚ and Pâ‚‚, then find Pâ‚-mv²/Pâ‚‚-mv². Contact angle for smaller pulley is 156â°, Groove angle is 36â° and coefficient of friction is 0.2.

A)

4.66

B)

5.36

C)

5.83

D)

6.21

Correct Answer : 5.83

Explaination : Pâ‚-mv²/Pâ‚‚-mv²=e^(fá½°/sinθ/2).

284 .

If belt tension in the two sides is 730N and 140N and belt is moving with a velocity of 10m/s, calculate the power transmitted.

A)

4.5kW

B)

5.9kW

C)

6.2kW

D)

None of the above

Correct Answer : 5.9kW

285 .

The belt tension is maximum when velocity of belt is 0.

A)

True

B)

It has a constant value

C)

It is max at v=infinity

D)

It is velocity independent

Correct Answer : It is max at v=infinity

Explanation : Pâ‚-mv²/Pâ‚‚-mv²=e^(fa/sinθ/2). Hence belt tension is maximum when v=0.

286 .

If maximum tension in the belt is 900N and allowable belt load is 500N. Calculate the number of belts required to transmit power.

A)

2

B)

3

C)

4

D)

5

Correct Answer : 2

287 .

Ribbed V belt is not generally recommended as the output speed keeps fluctuating.

A)

True

B)

No, it is generally recommended

C)

No variation in output speeds

D)

None of the above

Correct Answer : No, it is generally recommended

Explanation : There is no variation in output speed in case of ribbed V belts.

288 .

The intensity of normal pressure between the friction lining and the brake drum at any point is proportional to square of the vertical distance from the pivot.

A)

It is independent

B)

Inversely proportion to vertical distance

C)

Proportional to vertical distance linearly

D)

None of the above

Correct Answer : Proportional to vertical distance linearly

Explanation : It is proportional to the vertical distance linearly.

289 .

The coefficient of friction in internally expanding brakes is constant.

A)

True

B)

No, it varies with increase in speed linearly

C)

It decreases with increase in speed linearly

D)

None of the above

Correct Answer : True

Explanation : Coefficient of friction is constant in these types of brakes.

290 .

These kinds of brakes require little maintenance.

A)

Yes

B)

No

C)

Very much maintenance is required

D)

Depends on the working environment

Correct Answer : Yes

Explanation : Very little maintenance is required as there is less wear.

291 .

Moment of normal force and frictional forces about the pivot axis are 640000N-mm and 250000N-mm respectively. If force acts at a distance of 190mm from the pivoted point, calculate the actuating force.

A)

1078.6N

B)

2052.6N

C)

3223.5N

D)

4454.5N

Correct Answer : 2052.6N

Explaination : P=M(n)-M(f)/C.

292 .

Internally expanding brakes never suffer the problem of self-locking.

A)

True

B)

Wear might lead to self-locking

C)

Brakes are never self-locked

D)

None of the above

Correct Answer : Wear might lead to self-locking

293 .

In both simple band brake and differential band brake, at least one end of the band passes through fulcrum.

A)

One end

B)

Neither end

C)

Both the ends

D)

None of the above

Correct Answer : Both the ends

Explanation : In differential, neither end of the brake passes through fulcrum.

294 .

Band brake has complex construction with large number of parts.

A)

Yes

B)

It has simple construction

C)

It has simple constructions but large number of parts

D)

It has complicated construction but small number of parts

Correct Answer : It has simple construction

Explanation : Band brake has simple construction with small number of parts.

295 .

Band brakes require _____ maintenance.

A)

Little

B)

Zero

C)

Much

D)

None of the above

Correct Answer : Little

Explanation : There is relatively less maintenance required as there are small number of parts and hence chances of brake going out of order is less.

296 .

In drum brakes, as the temperature increases coefficient of friction ______

A)

increases

B)

decreases

C)

remains same

D)

Canâ€™t be determined

Correct Answer : Canâ€™t be determined

Explanation : Coeffecient of friction varies inversely with the temperature.

297 .

Disk brakes can be used for opposite rotation of disk also.

A)

They can be used

B)

Poor efficiency in opposite direction

C)

Both (A) and (B)

D)

No they are effective for one direction of motion only

Correct Answer : No they are effective for one direction of motion only

Explanation : Disk brakes are equally effective for both direction of motion.

298 .

The chain drive is same as gear drive.

A)

Yes

B)

No, it is intermediate between belt and gear drive

C)

It is superior to gear drive

D)

It is inferior to gear drive

Correct Answer : No, it is intermediate between belt and gear drive

Explanation : Chain drive is intermediate between belt drive and gear drive.

299 .

The maximum achievable efficiency of the chain drives is about 80%.

A)

It is always <40%

B)

It is about 50%

C)

It is about 75%

D)

It is about 96-98%

Correct Answer : It is about 96-98%

Explanation : Maximum achievable efficiency is around 96-98%.

300 .

The velocity of the chain is always constant in case of chain drive.

A)

Yes

B)

No, it can never be constant

C)

It is constant above a particular value

D)

Canâ€™t be stated

Correct Answer : No, it can never be constant

Explanation : Velocity isn’t constant in chain drive which results in non-uniform speed of the driven shaft.

301 .

In the designation '04B', pitch of the chain is?

A)

4mm

B)

6.35mm

C)

12.7mm

D)

None of the above

Correct Answer : 6.35mm

Explanation : Pitch=[04/16]x25.4mm.

302 .

Galling is a stick slip phenomenon.

A)

True

B)

No, it is only a slip phenomenon

C)

No, it is only a stick phenomenon

D)

Can't be stated

Correct Answer : True

Explanation : During high tension, welds are formed at the high spot of contacting area which are subsequently broken due to relative motion.

303 .

Wear ultimately results in ride in of the chain on sprocket teeth.

A)

True

B)

Ride up

C)

Ride out

D)

Ride down

Correct Answer : Ride out

Explanation : Wear causes ride out of chain.

304 .

The number of links of the chain should be always ______

A)

Odd

B)

Even

C)

Multiple of 3

D)

None of the above

Correct Answer : Even

Explanation : The odd number of teeth are meshed with even number of links.

305 .

Sum of number of links and number of teeth of the sprocket is _____

A)

Odd

B)

Even

C)

Odd or Even

D)

None of the above

Correct Answer : Odd

Explanation : Number of links are even while number of teeth on the sprocket are odd.

306 .

The driving sprocket has 19 teeth and rotates at 1100rpm. The pitch of the chain is 18mm. Calculate the velocity of the chain.

A)

5.1m/s

B)

5.6m/s

C)

5.8m/s

D)

6.3m/s

Correct Answer : 6.3m/s

Explanation : v=zpn/60×1000

307 .

In silent chain sprocket teeth have a rectangular profile.

A)

No circular

B)

No hyperbolic

C)

No trapezoidal

D)

Yes rectangular

Correct Answer : No trapezoidal

Explanation : They have a trapezoidal profile.

308 .

If centre distance for a chain drive is 750mm with number of teeth on the driving and driven sprockets being 40 and 20 respectively, then calculate the number of links required. Given: Pitch is taken as 19mm.

A)

109

B)

110

C)

111

D)

112

Correct Answer : 110

Explaination : 2(a/p) + (zâ‚+zâ‚‚)/2 +( zâ‚‚- zâ‚/2π)²xp/a.

309 .

Calculate the pitch circle diameter of the driving pulley is pitch is given as 18mm and sprocket has 19 teeth.

A)

102.66mm

B)

105.33mm

C)

109.36mm

D)

112.33mm

Correct Answer : 109.36mm

Explanation : D=p/sin(180/z).

310 .

Driving and driven pulleys are rotating at 1000rpm and 500rpm. If number of teeth on driving sprocket are 20, find number of teeth in the driven sprocket.

A)

10

B)

11

C)

40

D)

41

Correct Answer : 40

Explanation : nâ‚zâ‚=nâ‚‚zâ‚‚.

311 .

Which of the following are functions of bearings?

A)

Holding shaft in a correct position

B)

Transmit the force of the shaft to the frame

C)

Ensure free rotation of shaft with minimum friction

D)

All of the above

Correct Answer : All of the above

Explanation : Bearings are used for all the above listed purposes.

312 .

A_______ bearing supports the load acting along the axis of the shaft.

A)

Thrust

B)

Radial

C)

Transversal

D)

Longitudinal

Correct Answer : Thrust

Explanation : Thrust bearing supports load acting along axis of shaft.

313 .

Which of the following is measure of stiffness?

A)

Toughness

B)

Modulus of elasticity

C)

Resilience

D)

Modulus of plasticity

Correct Answer : Modulus of elasticity

Explanation : Stiffness is the ability of material to resist deformation under external load. Hence it is measured by modulus of elasticity.

314 .

In cycloidal gears contact area is

A)

Canâ€™t be determined

B)

Comparatively larger

C)

Comparatively smaller

D)

None of the above

Correct Answer : Comparatively larger

Explanation : Convex flank on one tooth meets with concave on the other thus increasing the contact area.

315 .

Cycloidal teeth consist of

A)

Epicycloid gear

B)

Hypocycloid curve

C)

Both hypocycloid curve and epicycloid curve

D)

None of the above

Correct Answer : Both hypocycloid curve and epicycloid curve

Explanation : It consist of both and thus are hard to manufacture.

316 .

Pressure angle is _____ in case of cycloidal teeth.

A)

Variable

B)

zero

C)

Constant

D)

None of the above

Correct Answer : Variable

Explanation : Cycloidal teeth consist of two profiles.

317 .

Diameteral pitch is 5, then calculate module of the gear.

A)

0.2

B)

0.4

C)

5

D)

10

Correct Answer : 0.2

Explanation : Module is the inverse of diameteral pitch.

318 .

Deep groove ball bearings creates a lot of noise.

A)

Yes

B)

They create very less noise

C)

Depends on the application

D)

No reference frame for comparison is mentioned

Correct Answer : They create very less noise

Explanation : They create very less noise due to point contact.

319 .

Deep groove ball bearing has immense rigidity.

A)

True

B)

It has line contact

C)

It has surface contact

D)

No it has point contact and hence low rigidity

Correct Answer : No it has point contact and hence low rigidity

Explanation : Due to point contact, rigidity is not so good.

320 .

The angular play bearing must be mounted without axial play.

A)

Yes

B)

Canâ€™t be stated

C)

Little tolerance is adjusted

D)

Little tolerance is necessary

Correct Answer : Yes

Explanation : There is no tolerance of misalignment.

321 .

Which of the following cannot tolerate misalignment?

A)

Thrust ball bearings

B)

Cylinder roller bearing

C)

Angular contact bearing

D)

All of the above

Correct Answer : All of the above

Explanation : All of these require précised alignment.

322 .

Which of the following cannot take radial load?

A)

Taper roller bearing

B)

Cylindrical Roller bearing

C)

Thrust ball bearing

D)

None of the above

Correct Answer : Thrust ball bearing

Explanation : There is no inclination in the line of reaction and hence only thrust loads can be carried.

323 .

Taper rolling supports________.

A)

Axial loads

B)

Thrust loads

C)

Both axial and thrust loads

D)

None of the above

Correct Answer : Both axial and thrust loads

Explanation : The line of reaction makes an angle with the axis of bearing and hence both type of loads can be carried.

324 .

If centre distance between the two gears on same shaft is unequal to the centre distance on the other two gears on the second shaft, then this gear train is called reverted gear train.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : False

Explaination : The centre distance is equal in both the shafts.

325 .

If one gear is fixed while the other gear has motion of two types i.e. rotary about its own axis and rotation about axis of fixed gear, than the gear train is _____

A)

Epicyclic gear train

B)

Kepler gear train

C)

Reverted gear train

D)

None of the above

Correct Answer : Epicyclic gear train

Explanation : Definition of epicyclic gear train.

326 .

Which of the following are true about epicyclic gear train?

A)

Crank is called sun carrier

B)

Fixed gear is called sun gear

C)

Rotating gear are called earth gear

D)

None of the above

Correct Answer : Fixed gear is called sun gear

Explanation : Rotating gears are called planet gears.

327 .

Static load is defined as the load acting on the bearing when shaft is _____

A)

Stationary

B)

Rotating at rpm<5

C)

Rotating at rpm<10

D)

None of the above

Correct Answer : Stationary

Explanation : As name suggests, static load means load during stationary position of the shaft.

328 .

Which of the following is expression for stribeck equation?(Number of balls=z)?

A)

C=kdÂ²z/15

B)

C=kdÂ²z/10

C)

C=kdÂ²z/5

D)

None of the above

Correct Answer : C=kdÂ²z/5

Explanation : C=(1/5)zP and P=kd².

329 .

In the expression of dynamic load capacity P=XVF(r) + YF(a), V stands for?

A)

Radial factor

B)

Thrust factor

C)

Both (A) and (B)

D)

Race rotation factor

Correct Answer : Race rotation factor

Explanation : It represent race rotation factor which depends upon whether inner race is rotating or outer race.

330 .

Scoring is a ________ phenomenon.

A)

In-out

B)

Stick-slip

C)

Fatigue

D)

Fracture

Correct Answer : Stick-slip

Explanation : Alternative welding and shearing takes place.

331 .

Extreme pressure causes ______ wear in the bearing parts.

A)

Corrosive

B)

Pitting

C)

Abrasive

D)

All of the above

Correct Answer : Corrosive

Explanation : Extreme pressure elements in EP additives are added in lubricating oils.

332 .

A rolling contact bearing is specified as X307. Determine the series.

A)

Light series

B)

Heavy series

C)

Medium series

D)

Extra light series

Correct Answer : Medium series

Explanation : 1- Extra light series,2-Light series,3-Medium series,4-heavy series.

333 .

The bearing is subjected to a radial load of 4000N. Expected life for 90% bearings is 9000h and shaft is rotating at 1500rpm. Calculate the dynamic load capacity.

A)

42.21kN

B)

37.29kN

C)

35.22kN

D)

26.33kN

Correct Answer : 37.29kN

Explanation : C=4000x(810)â…“

334 .

Calculate the bearing life if expected life for 90% bearings is 9000h and shaft is rotating at 1500rpm.

A)

810 h

B)

850h

C)

850 million rev

D)

810 million rev

Correct Answer : 810 million rev

Explanation : L=60x1500x9000/10â¶ million rev.

335 .

Interference is caused by?

A)

Large size of dedendum

B)

Overlapping of tooth profiles

C)

Meshing of involute and no-involute profiles

D)

All of the above

Correct Answer : All of the above

Explanation : In some cases, portion of tooth below base circle is not involute due to large dedendum. This leads to overlapping of involute portion of teeth with the non-involute portion of the teeth.

336 .

Backlash is defined as______.

A)

Other name for interference

B)

Amount by which engaging tooth thickness exceeds the tooth space

C)

Difference in the width of tooth space and engaging tooth thickness

D)

None of the above

Correct Answer : Difference in the width of tooth space and engaging tooth thickness

Explanation : Backlash is the amount by which tooth space exceeds the engaging tooth thickness.

337 .

The amount of backlash depends on________.

A)

Module

B)

Centre distance

C)

Diameteral pitch

D)

All of the above

Correct Answer : All of the above

Explanation : Module and diameteral pitch are the same thing, and centre distance is also a factor while deciding the magnitude of the backlash.

338 .

The two teeth have thickness tâ‚ and tâ‚‚. If backlash of tâ‚ is greater than that of tâ‚‚, than

A)

tâ‚ < tâ‚‚

B)

tâ‚ > tâ‚‚

C)

tâ‚ = tâ‚‚

D)

None of the above

Correct Answer : tâ‚ < tâ‚‚

Explanation : Backlash=Tooth space-tooth thickness, greater the backlash lower is the tooth thickness.

339 .

Thick film lubrication describes a phenomenon where two surfaces are _______ separated.

A)

Not

B)

Completely

C)

Partially

D)

None of the above

Correct Answer : Completely

340 .

A journal bearing is a ______ contact bearing working on the hydrodynamic lubrication and which supports load in____ direction.

A)

Rolling, Axial

B)

Sliding, Radial

C)

Sliding, Axial

D)

Rolling, Radial

Correct Answer : Sliding, Radial

Explanation : This is how journal bearing works. It derives its name from the portion of the shaft inside the bearing.

341 .

A clearance bearing is design accurately to keep the radius of journal and bearing equal.

A)

True

B)

Journal radius is kept smaller

C)

Journal radius is kept larger

D)

Canâ€™t be determined

Correct Answer : Journal radius is kept smaller

342 .

Footstep bearing is an axial load bearing.

A)

True

B)

Shear load

C)

Thrust load

D)

None of the above

Correct Answer : Thrust load

Explanation : It is a thrust bearing in which shaft end is in contact with bearing surface.

343 .

If we exclude the cost factor, which bearing is preferred?

A)

Hydrostatic

B)

Hydrodynamic

C)

Both are equally preferred

D)

Cannot be determined

Correct Answer : Hydrostatic

Explanation : High load capacity, no starting friction and no rubbing action.

344 .

There are ____ standard systems for the shape of gear teeth.

A)

1

B)

2

C)

3

D)

4

Correct Answer : 3

Explanation : 14.5â° full depth involute system, 20â° full depth involute system and 20â° stub involute system.

345 .

20â° stub involute system have comparatively smaller interference.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : True

Explanation : They have shorter addendum and shorter dedendum.

346 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the bottom clearance.

A)

1.75mm

B)

1.25mm

C)

2.5mm

D)

None of the above

Correct Answer : 1.25mm

Explanation : C = 0.25m = 0.25x5mm = 1.25mm.

347 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the tooth thickness.

A)

5.44mm

B)

6.23mm

C)

7.854mm

D)

8.16mm

Correct Answer : 7.854mm

Explanation : T = 1.5708xm = 1.5708x5mm = 7.854mm.

348 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the centre distance.

A)

269mm

B)

283mm

C)

305mm

D)

350mm

Correct Answer : 350mm

Explanation : C = m(z(p)+z(g))/2.
C = 5(25 + 115)/2 => 700/2 => 350mm.

349 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate pitch circle diameter of the pinion.

A)

95mm

B)

105mm

C)

115mm

D)

125mm

Correct Answer : 125mm

Explanation : D = 5×25 = 125mm.

350 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the pitch circle diameter of the gear.

A)

31mm

B)

254mm

C)

475mm

D)

575mm

Correct Answer : 575mm

Explanation : D = 5×115 = 575mm.

351 .

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the dedendum.

A)

4.75mm

B)

5.6mm

C)

6.25mm

D)

6.68mm

Correct Answer : 6.25mm

Explanation : H = 1.25xm = 1.25x5mm = 6.25mm.

352 .

Viscosity is defined as the external resistance offered by a fluid to change its shape or relative motion of its parts.

A)

Yes

B)

It is internal resisting force

C)

It is not offered but exerted on the fluids

D)

None of the above

Correct Answer : It is internal resisting force

Explanation : It is an internal resisting force.

353 .

Calculate the kinematic viscosity if Saybolt viscosity is 400cSt.

A)

86.32SUS

B)

87.55SUS

C)

40.25SUS

D)

400SUS

Correct Answer : 87.55SUS

Explanation : z=0.22t-[180/t] where t=400.

354 .

Which of the following lubricant has least rate of change of viscosity w.r.t temperature.

A)

VI=20

B)

VI=30

C)

VI=40

D)

VI=50

Correct Answer : VI=50

Explanation : Greater the VI, lesser is the rate of change w.r.t temperature.

355 .

Which of the following are not true for petroff's equation?

A)

Frictional torque is given by fprÂ²l

B)

Bearing is subjected to light load

C)

Is used to find coefficient of friction

D)

Shaft is considered concentric with the bearing

Correct Answer : Frictional torque is given by fprÂ²l

Explanation : M=fWr=f(2prl)r, W=projected area of bearing x pressure.

356 .

For a hydrostatic thrust bearing, Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm,film thickness=0.15mm,viscosity of lubricant=160SUS and specific gravity=0.86.
Calculate frictional power loss.

A)

4.2kW

B)

2.3kW

C)

3.56kW

D)

None of the above

Correct Answer : 3.56kW

Explaination : kW=µn²(225â´-155â´)/hx58.05×10â¶.

357 .

For a hydrostatic thrust bearing, Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm, film thickness=0.15mm, viscosity of lubricant=160SUS and specific gravity=0.86.

Calculate flow requirement

A)

0.89l/s

B)

28.8l/min

C)

38.94l/min

D)

None of the above

Correct Answer : 38.94l/min

Explaination : Q=πPháµŒ/6µln(225/155) whereµ=z/10â¹ and z=0.86x[0.22×160-180/160]. µ=29.3 x 10¯â¹N-s/mm².

358 .

In hydrodynamic lubrication, film thickness remains unaffected by change in speeds.

A)

True

B)

Increase with increase in speed

C)

Decrease with increase in speed

D)

Disappear as the speed tends to infinty

Correct Answer : Increase with increase in speed

Explanation : As speed increases more and more lubricant is forces and pressure builds up thus separating the two surfaces. There is transition from thin film thick film.

359 .

Among spur gear and helical gear, which has smooth engagement and thus lesser noise?

A)

Spur Gears

B)

Helical Gears

C)

Both have equal noises

D)

None of the above

Correct Answer : Helical Gears

360 .

Among the normal module and transverse module, which one has greater value?

A)

Normal Module

B)

Insufficient information

C)

Transverse Module

D)

None of the above

Correct Answer : Transverse Module

Explanation : Normal Module=Transverse modulexCos(helix angle).

361 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the transverse module.

A)

3.7mm

B)

3.9mm

C)

4.1mm

D)

4.3mm

Correct Answer : 4.3mm

Explaination : m=4/Cos(22â°).

362 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the transverse pressure angle in degrees.

A)

20.4

B)

19.6

C)

18.4

D)

17.9

Correct Answer : 20.4

Explaination : taná¾°=tan(19â°)/Cos(22â°).

363 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the pitch circle diameter of pinion.

A)

52.6mm

B)

56.6mm

C)

64.7mm

D)

68.8mm

Correct Answer : 64.7mm

Explaination : d=zxm/Cos(22)

364 .

If tangential component of force on tooth is 200N and helix angle is 25â°, calculate the axial component of the force.

A)

93.26N

B)

200N

C)

215.6N

D)

302.5N

Correct Answer : 93.26N

Explanation : P(a)=200xtan(25).

365 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the dedendum circle diameter of the pinion.

A)

54.7mm

B)

59.2mm

C)

64.5mm

D)

None of the above

Correct Answer : 54.7mm

Explaination : D(f)=m[z/Cos(22) – 2.5].

366 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the centre distance.

A)

145.4mm

B)

132.6mm

C)

125.4mm

D)

118.65mm

Correct Answer : 118.65mm

Explaination : C=Sum of diameter of pinion and gear/2.

367 .

A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22â° and normal pressure angle 19â°. The normal module is taken as 4mm. Calculate the pitch circle diameter of the gear.

A)

142.6mm

B)

172.6mm

C)

180.3mm

D)

202.4mm

Correct Answer : 172.6mm

Explaination : d=zxm/Cos(22)

368 .

A single transverse weld is preferred over double transverse fillet weld.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : False

Explanation : A single transverse weld is not preferred because the edge of the plate which is not welded can warp out of shape.

369 .

The fundamental equation for viscous flow is given by âˆ†pbháµŒ/6Âµl where symbols have their usual meanings.

A)

6 is to be replaced by 3

B)

6 is to be replaced by 9

C)

6 is to be replaced by 12

D)

6 is to be replaced by 15

Correct Answer : 6 is to be replaced by 12

Explanation : It is givenby âˆ†pbháµŒ/12µl.

370 .

A pair of helical gears consist of 25 teeth pinion gear meshing with a 90 teeth gear. Calculate the ratio factor.

A)

0.74

B)

0.88

C)

1.44

D)

1.57

Correct Answer : 1.57

Explanation : Ratio factor Q=2×90/90+25.

371 .

A pair of helical gears consist of 25 teeth pinion gear meshing with a 90 teeth gear. Calculate the material constant k If surface hardness is 260BHN.

A)

0.64N/mmÂ²

B)

0.88N/mmÂ²

C)

1.08N/mmÂ²

D)

2.66N/mmÂ²

Correct Answer : 1.08N/mmÂ²

Explanation : K=0.16x[BHN/100]²

372 .

A pair of helical gears consist of 25 teeth pinion gear meshing with a 90 teeth gear. Calculate the wear strength If surface hardness is 260BHN. Also face width=35mm, module=4mm and helix angle=25â°.

A)

443.5N

B)

1014.2N

C)

3245.6N

D)

7971.9N

Correct Answer : 7971.9N

Explaination : S=bQdK/cos²Æœ where Æœ=25â°, d=zm/cosÆœ, Q=2×90/90+25, K=0.16x[BHN/100]².

373 .

A pair of helical gears consist of 25 teeth pinion gear meshing with a 90 teeth gear. Calculate the tangential force If surface hardness is 260BHN. Also face width=35mm, module=4mm and helix angle=25â°. The velocity of operation is 3.5m/s and service factor 1.5.

A)

3983.7

B)

3226.5N

C)

2012.6N

D)

1136.5N

Correct Answer : 3983.7

Explaination : S=1.5xP/C where C=5.6/5.6+√v and S=bQdK/cos²Æœ where Æœ=25â°, d=zm/cosÆœ, Q=2×90/90+25, K=0.16x[BHN/100]².

374 .

A herringbone speed reducer consist of 20 teeth pinion driving a 100 teeth gear. The normal module of gear is 2mm. The face width of each half is 30mm and Lewis factor is 0.4. If permissible bending stress is 500N/mm², then calculate the beam strength.

A)

8000N

B)

10000N

C)

12000N

D)

15000N

Correct Answer : 12000N

Explaination : S=mbσY

375 .

Calculate the shaft angle for same hand of helix if helix angle of two gears are 20â° and 17â°.

A)

3â°

B)

17â°

C)

20â°

D)

37â°

Correct Answer : 37â°

Explanation : For same hand of helix, shaft angle=sum of helix angles of two gears

376 .

A herringbone speed reducer consist of 20 teeth pinion driving a 100 teeth gear. The normal module of gear is 2mm. The face width of each half is 30mm and Lewis factor is 0.4. Calculate the material constant K if surface hardness is 400BHN.

A)

1.25 N/mm²

B)

2.56N/mm

C)

3.25N/mm²

D)

4.05 N/mm²

Correct Answer : 3.25N/mm²

Explaination : K=0.16x[BHN/100]²

377 .

A herringbone speed reducer consist of 20 teeth pinion driving a 100 teeth gear. The normal module of gear is 2mm. The face width of each half is 30mm and Lewis factor is 0.4. Calculate the ratio factor Q.

A)

1.2

B)

1.4

C)

1.5

D)

1.7

Correct Answer : 1.7

Explaination : Q=2×100/100+20

378 .

Which of the following can be used for power transmission in intersecting shafts.

A)

Bevel Gear

B)

Spur Gear

C)

Helical Gear

D)

None of the above

Correct Answer : Bevel Gear

Explanation : Bevel gears are used for power transmission in case of intersecting shafts

379 .

The two gears are said to have conjugate motion if

A)

Variable angular velocity ratio

B)

They have constant angular velocity ratio

C)

Infinitely small angular velocity ratio

D)

None of the above

Correct Answer : They have constant angular velocity ratio

Explanation : Two gear are said to have conjugate motion and tooth profiles are said to have conjugate curves if they have constant angular velocity ratio

380 .

Herringbone gear can be used in

A)

Parallel shafts only

B)

Intersecting shafts only

C)

Both intersection and parallel shafts

D)

None of the above

Correct Answer : Parallel shafts only

381 .

Bevel gears impose ____ loads on the shafts.

A)

Radial

B)

Thrust

C)

Radial and thrust

D)

Neither radial nor thrust

Correct Answer : Radial and thrust

Explanation : Bevel gears have the shape of a truncated cone and tooth is cut straight or spiral.

382 .

For a constant velocity ratio, the common normal to the tooth profile at point of contact must pass through a continuously variable point.

A)

True

B)

It pass through a fixed point

C)

Constant velocity ratio isn’t required, hence variable point is preferred

D)

None of the above

Correct Answer : It pass through a fixed point

Explaination : It must pass through a fixed point called pitch to maintain a constant velocity ratio.

383 .

Required velocity ratio is 60:1, which of the following are recommended?

A)

Spur

B)

Bevel

C)

Worm

D)

None of the above

Correct Answer : Worm

Explanation : For high speed reduction ratio, worm gears are recommended.

384 .

Greater the velocity ratio, smaller the gearbox.

A)

True

B)

Greater the gearbox

C)

Size of gearbox remains unaffected

D)

None of the above

Correct Answer : Greater the gearbox

Explanation : Greater velocity leads to increase in size of gear wheel which results in size of gearbox.

385 .

Straight bevel gears are easy to design and manufacture and give reasonably good service with quieter operation.

A)

True

B)

No, vibration problem

C)

No, noise problem

D)

None of the above

Correct Answer : No, noise problem

Explanation : They produce a lot of noise while working.

386 .

Which of the following creates smoother motion?

A)

Spiral bevel gears

B)

Straight bevel gears

C)

Equal for straight and spiral

D)

None of the above

Correct Answer : Spiral bevel gears

Explanation : Spiral bevel gear has smooth engagement which results in quieter operation.

387 .

Crown gears having a pitch angle of 90â° are mounted on shafts intersecting at an angle

A)

<90

B)

>90

C)

=90

D)

None of the above

Correct Answer : >90

Explanation : Application of crown gear according to its structure.

388 .

When two hyperboloids are rotated, the resulting motion is

A)

Rotary

B)

Sliding

C)

Turning

D)

Combination of turning and sliding

Correct Answer : Combination of turning and sliding

Explanation : There is turning as well as sliding motion.

389 .

Hypoid gears have the following characteristics.

A)

Curved teeth

B)

Efficiency of 97%

C)

Mounted on non -parallel non intersecting shafts

D)

All of the above

Correct Answer : All of the above

Explanation : It has curved teeth and are mounted on non-parallel non intersecting shafts with efficiency of 96-98%.

390 .

Zerol gears give lesser contact ratio.

A)

True

B)

No, larger contact ratio

C)

Zero contact

D)

None of the above

Correct Answer : No, larger contact ratio

Explanation : Zerol gears have more gradual contact and slighter larger contact ratio.

391 .

If worm helix angle is 30â°, then worm should have at least ___ threads.

A)

5

B)

6

C)

7

D)

8

Correct Answer : 5

Explanation : The permissible helix angle is 6â° and hence there should be at least five threads i.e. 30/6.

392 .

A pair of worm gear is written as 2/40/12/6. Calculate the centre distance.

A)

40mm

B)

80mm

C)

156mm

D)

200mm

Correct Answer : 156mm

Explanation : C=m(q+z)/2 where m=6mm, q=12 and z=40.

393 .

If tangential force on worm is 1500N, then axial force on worm wheel will be?

A)

750N

B)

3000N

C)

1500N

D)

1500âˆš2 N

Correct Answer : 1500N

Explanation : Pâ‚‚(axial)=Pâ‚(tangential)

394 .

A pair of worm gear is written as 2/40/12/6. Calculate the throat diameter of the worm wheel.

A)

190.44mm

B)

220.5mm

C)

246.4mm

D)

251.7mm

Correct Answer : 251.7mm

Explanation : d(t)=m[z+4cosϒ-2] where ϒ=9.46â° is the lead angle. tanϒ=2/12, z=40 and m=6mm

395 .

If pitch angle and addendum angles are 5â° and 12â° respectively, then face angle is equal to?

A)

5â°

B)

7â°

C)

12â°

D)

17â°

Correct Answer : 17â°

Explanation : Face angle=pitch angle+ addendum angle

396 .

If back cone distance is 12mm and module at large end of the tooth is 4mm, then formative number of teeth will be?

A)

3

B)

4

C)

6

D)

12

Correct Answer : 6

Explanation : Formative number=2r/m.

397 .

If back cone distance is 12mm and module at large end of the tooth is 4mm, and virtual number of teeth is 12 then find the diameter of the tooth.

A)

2

B)

3

C)

4

D)

5

Correct Answer : 2

Explanation : 12/z = 2×12/4.

398 .

Calculate the pitch angle if pitch circle diameter of the pinion and gear are 150mm and 210mm.

A)

28.14â°

B)

35.54â°

C)

36.22â°

D)

63.22â°

Correct Answer : 35.54â°

Explanation : tanϒ=D(p)/D(g)=150/210.

399 .

Calculate the radius of pinion at midpoint along the face width if PCD of pinion is 150mm and of gear is 210mm. Also face width of the tooth is 35mm.

A)

56.35mm

B)

58.69mm

C)

64.83mm

D)

66.57mm

Correct Answer : 64.83mm

Explanation : r=(Dp/2)-(bsinϒ/2)

400 .

Calculate the radial component of gear tooth force if power transmitted is 6kW and diameters of pinion and gear are 150mm and 210 mm with face width of tooth being 35mm. Power is transmitted at 3000rpm. Also pressure angle is 20â°.

A)

332.6N

B)

489.2N

C)

739.2N

D)

996.6N

Correct Answer : 739.2N

Explaination : P radial=P tangential x[tan20 Cos ϒ]

401 .

Calculate the axial component of gear tooth force if power transmitted is 6kW and diameters of pinion and gear are 150mm and 210 mm with face width of tooth being 35mm. Power is transmitted at 3000rpm. Also pressure angle is 20â°.

A)

448.21N

B)

528.06N

C)

660.05N

D)

886.6N

Correct Answer : 528.06N

Explaination : P radial=P tangential x[tan20 Sin ϒ]

402 .

Which of the following are functions of flywheel?

A)

Reduce amplitude of speed fluctuations

B)

Reduce power capacity of the electric motor

C)

Store and release energy during work cycle

D)

All of the above

Correct Answer : All of the above

Explanation : Flywheel provides uniform motion by storing energy during idle positions and using this at actual operational time and thus reducing the power capacity of the electric motor.

403 .

When comes down to stress reduction, which one is preferred?

A)

Split flywheel

B)

Solid flywheel

C)

Both have equal stresses

D)

None of the above

Correct Answer : Split flywheel

Explanation : The arms are free in split flywheel to contract and hence are better for stress reduction.

404 .

If load on the engine is constant, the mean speed will be constant and ___ will not operate.

A)

Flywheel

B)

Governor

C)

Both flywheel and governor

D)

None of the above

Correct Answer : Governor

Explanation : Governor is used to control the mean speed and if mean speed is held constant then the governor will not operate.

405 .

When the driving torque is more than load torque, flywheel is ______

A)

Accelerated

B)

Decelerated

C)

Constant velocity

D)

None of the above

Correct Answer : Accelerated

Explanation : I[dω/dt]=Driving torque-load torque.

406 .

Lewis equation is used to obtain ____ strength of bevel gears.

A)

Wear

B)

Abrasive

C)

Beam

D)

Corrosive

Correct Answer : Beam

Explanation : According to Lewis equation, Beam strength=product of module, face width of elemental section, permissible bending stress and Lewis form factor.

407 .

Beam strength indicates the maximum value of the ___________ force at the large end of the tooth that the tooth can transmit without bending.

A)

Axial

B)

Radial

C)

Both (A) and (B)

D)

Tangential

Correct Answer : Tangential

Explanation : Beam strength is analysed by using the pitch radius at the larger end of the tooth.

408 .

Wear strength of the bevel gear can be calculated by using ________ equation.

A)

Lewis

B)

Rayleigh

C)

Newtonian

D)

Buckingham

Correct Answer : Buckingham

Explanation : Bevel gear is considered to be equivalent to a formative spur gear in a plane which is perpendicular to the large end and hence Buckingham equation is applied.

409 .

If velocity is 5m/s, then velocity factor for a cut teeth is

A)

0.55

B)

0.66

C)

1.55

D)

1.66

Correct Answer : 0.55

Explanation : C=6/6+v

410 .

If surface hardness for a par of bevel gears is 400BHN, then material constant is

A)

3N/mmÂ²

B)

2.56N/mmÂ²

C)

1.44N/mmÂ²

D)

0.98N/mmÂ²

Correct Answer : 2.56N/mmÂ²

Explanation : K=0.16x[BHN/100]²

411 .

Calculate the wear strength for a pair of bevel gears having face width=20mm, module=5mm, No of teeth on pinion and gear 25 and 40 respectively and PCD of pinion=75mm.

A)

3668.5N

B)

4884.5N

C)

4117.3N

D)

5126.6N

Correct Answer : 4884.5N

Explaination : S=0.75xbxQxDxK/Cos ϒ. Tan ϒ=25/40 or ϒ=32â°. Q=2×40/ [40+25xtan(32)] K=0.16x[BHN/100]².

412 .

If service factor is 1.4 & tangential ad dynamic load is 1180N and 1500N respectively, then calculate the effective load.

A)

2236N

B)

2889N

C)

3152N

D)

3662N

Correct Answer : 3152N

Explanation : Effective load=1.4×1180 + 1500.

413 .

Calculate the coefficient of fluctuation of speed if maximum speed is 2500rpm and minimum speed is 1800rpm.

A)

0.33

B)

0.44

C)

1.33

D)

1.44

Correct Answer : 0.33

Explanation : C=2[(Max-Min)/(Max+Min)]

414 .

Calculate the coefficient of steadiness if maximum speed of flywheel is 2500rpm and minimum speed is 1800rpm.

A)

0.33

B)

0.44

C)

3.99

D)

3.03

Correct Answer : 3.03

Explanation : C=1.Coeffecient of fluctuation of speed.

415 .

Tangential stress in a cylinder is given by [symbols have their usual meanings].

A)

PD/4t

B)

PD/2t

C)

2PD/t

D)

4PD/t

Correct Answer : PD/2t

Explanation : Considering equilibrium in half portion of cylinder of unit length, DP=2σt.

416 .

Longitudinal stress in a cylinder is given by [symbols have their usual meanings].

A)

PD/2t

B)

2PD/t

C)

PD/4t

D)

4PD/t

Correct Answer : PD/4t

Explanation : Considering equilibrium PxπD²/4=σxπDt.

417 .

A seamless cylinder of storage capacity of 0.03máµŒis subjected to an internal pressure of 21MPa. The ultimate strength of material of cylinder is 350N/mm².Determine the length of the cylinder if it is twice the diameter of the cylinder.

A)

270mm

B)

350mm

C)

400mm

D)

540mm

Correct Answer : 540mm

Explaination : 0.03=πd²L/4 and L=2d.

418 .

A seamless cylinder of storage capacity of 0.03máµŒis subjected to an internal pressure of 21MPa. The ultimate strength of material of cylinder is 350N/mm².Determine the thickness of the cylinder if it is twice the diameter of the cylinder.

A)

4mm

B)

8mm

C)

12mm

D)

16mm

Correct Answer : 8mm

Explaination : t=PD/2σ.

419 .

The piston rod of a hydraulic cylinder exerts an operating force of 10kN. The allowable stress in the cylinder is 45N/mm². Calculate the thickness of the cylinder using Lame’s equation. Diameter of the cylinder is 40mm and pressure in cylinder is 10MPa.

A)

2.05mm

B)

4.2mm

C)

5.07mm

D)

None of the above

Correct Answer : 5.07mm

Explaination : t=D/2[√[σ+ P /σ-P] -1 ]

420 .

There are ____ types of liners.

A)

1

B)

2

C)

3

D)

4

Correct Answer : 2

Explanation : Dry liners and wet liners.

421 .

If no re boring allowance is to be given, then thickness of cylinder wall is max pressure is 3.5N/mmÂ², bore diameter=200mm and permissible tensile stress is 40N/mmÂ².

A)

7mm

B)

8mm

C)

9mm

D)

10mm

Correct Answer : 9mm

Explanation : t=pD/2σ=8.75mm

422 .

If diameter of cylinder of bore is 120mm, then thickness of the cylinder will be

A)

6mm

B)

7mm

C)

12mm

D)

Information not sufficient

Correct Answer : 7mm

Explanation : t=0.045D + 1.6.

423 .

If diameter of cylinder bore is 120mm, then thickness of dry liner will be

A)

2.2mm

B)

3.6mm

C)

4.8mm

D)

6mm

Correct Answer : 3.6mm

Explanation : t= 0.03D to 0.035D.

424 .

If nominal diameter of bolt used is 20mm, then find the radial distance between outer diameter of flange and pitch circle diameter of studs.

A)

36mm

B)

32mm

C)

28mm

D)

24mm

Correct Answer : 28mm

Explanation : r=d+6 to 1.5d i.e. 26mm to 30mm.

425 .

If diameter of cylinder bore is 120mm, then thickness of water jacket wall will be

A)

2.56mm

B)

4.26mm

C)

5.25mm

D)

All of the above

Correct Answer : All of the above

Explanation : p=t/3 to 3t/4, where t= thickness of cylinder wall=7mm.

426 .

If diameter of cylinder bore is 120mm, then thickness of water cylinder flange will be

A)

7.8mm

B)

8.8mm

C)

10.2mm

D)

12mm

Correct Answer : 8.8mm

Explanation : q=1.2t to 1.4t

427 .

Autogreggate is a process of ___ stressing the cylinder.

A)

Pre

B)

Post

C)

Over

D)

None of the above

Correct Answer : Pre

Explanation : It is a pre stressing phenomenon to improve pressure capacity.

428 .

A compound cylinder consists of

A)

2 jackets

B)

2 cylinders

C)

Cylinder and a jacket

D)

At least two cylinders

Correct Answer : Cylinder and a jacket

Explanation : Inner diameter of jacket increase and outer diameter of cylinder decreases when the jacket is heated.

429 .

A high pressure cylinder consists of a steel tube with inner and outer diameters 30 and 60mm respectively. It is jacketed by an outer steel tube, having an outer diameter of 90mm. Maximum principal stress induced is 80N/mm². Calculate the radial stresses due to shrink shift in jacket.

A)

-1.824[(45/r) ² – 1]

B)

1.824[(45/r) ² – 1]

C)

+2.56[(45/r) ² – 1]

D)

None of the above

Correct Answer : -1.824[(45/r) ² – 1]

Explaination : σ(r)=-PDâ‚‚²[Dâ‚ƒ²/4r² – 1]/ [Dâ‚ƒ²-Dâ‚‚²].

430 .

A high pressure cylinder consists of a steel tube with inner and outer diameters 30 and 60mm respectively. It is jacketed by an outer steel tube, having an outer diameter of 90mm. Maximum principal stress induced is 80N/mm². Calculate the radial stress due to shrink shift in inner tube.

A)

-3.04[1-(10/r) ²]

B)

-3.04[1-(15/r) ²]

C)

+3.04[1-(10/r) ²]

D)

+3.04[1-(15/r) ²]

Correct Answer : -3.04[1-(15/r) ²]

Explaination : σ(r)= σ(r)=-PDâ‚‚²[1-Dâ‚²/4r² ]/ [Dâ‚‚²-Dâ‚²].

431 .

A high pressure cylinder consists of a steel tube with inner and outer diameters 30 and 60mm respectively. It is jacketed by an outer steel tube, having an outer diameter of 90mm. Maximum principal stress induced is 80N/mm². In service the cylinder is further subjected to an internal pressure of 25MPa. Calculate the tangential stress in compound cylinder.

A)

-3.75[(45/r) ² -1]

B)

-3.75[(45/r) ² +1]

C)

+3.75[(45/r) ² +1]

D)

-6.75[(45/r) ² + 1]

Correct Answer : +3.75[(45/r) ² +1]

Explaination : σ(t)=+PDâ‚²[1+ Dâ‚ƒ²/4r² ]/ [Dâ‚ƒ²-Dâ‚²]. Here P=30.

432 .

An unfired pressure vessel is used to carry stem, gases or fluids at pressure

A)

Less than atmospheric pressure

B)

Greater than atmospheric pressure

C)

Equal to atmospheric pressure

D)

None of the above

Correct Answer : Greater than atmospheric pressure

433 .

Which of the following isn't true about oil seals?

A)

Cheap

B)

Can be used over a wide range of lubricating oils

C)

Canâ€™t tolerate misalignment

D)

All of the above

Correct Answer : Canâ€™t tolerate misalignment

Explanation : Oil seals can tolerate the misalignment to some extent.

434 .

Bucking of column means

A)

Axial deflection

B)

Lateral deflection

C)

Torsional deflection

D)

None of the listed

Correct Answer : None of the listed

Explanation : Buckling is characterised by lateral deflection but it is different from lateral deflection as there is sudden lateral deflection in buckling unlike lateral deflection where there is gradual deflection.

435 .

Slenderness ratio is [l= length of column and k= least radius of gyration of cross section about its axis].

A)

l/k

B)

k/l

C)

l/2k

D)

k/2l

Correct Answer : l/k

Explanation : It is a ratio of length to least radius of gyration.

436 .

Cast iron column with a slenderness ratio of 75 are

A)

Short Columns

B)

Long Columns

C)

Very short columns

D)

None of the above

Correct Answer : Short Columns

Explanation : Cast iron column with a slenderness ratio <80are short columns.

437 .

The wire rope is subjected to

A)

Tensile Stress

B)

Bending Stress

C)

Both bending and tensile stress

D)

None of the above

Correct Answer : Both bending and tensile stress

Explanation : There is direct tensile stress due to load being raised as well as bending stress.

438 .

Small sheaves are preferred over large sheaves on what parameters?

A)

Higher cost of small sheaves

B)

Increasingly centrifugal force in large sheaves

C)

Preferring centrifugal force reduction even for more money

D)

None of the above

Correct Answer : Increasingly centrifugal force in large sheaves

Explanation : Larger sheaves have higher centrifugal forces and higher cost because more material is used in their construction.

439 .

Which type of rope drum is preferred?

A)

Drums with helical grooves

B)

Plain cylindrical drums

C)

Both are equally preferred

D)

None of the above

Correct Answer : Drums with helical grooves

Explanation : They have more bearing surface of the drum and prevent friction between adjacent turns of the rope.