Mechanical Engineering - Theory of Machines Quiz (or) MCQ

1 .

Which of the following mechanism is an approximately straight-line motion mechanism?

A)

Watt's mechanism

B)

Hart's mechanism

C)

Peaucellier mechanism

D)

Scott Russell's mechanism

Correct Answer : Watt's mechanism

Explanation : Watt’s consists of three links. Two of them are of equal length whereas one is shorter. Due to the rotation motion of the longer links, the center of the shorter link traces an approximate straight line. Out of the following mechanism, Watt’s mechanism is an approximately straight line mechanism whereas the rest are exact straight line mechanisms.

2 .

In which of the following mechanism the relative motions of the rigid bodies are in one plane or in parallel planes?

A)

planar mechanism

B)

spatial mechanism

C)

flexure mechanism

D)

spherical mechanism

Correct Answer : planar mechanism

Explanation : In a planar mechanism, all particles describe plane curves in space and all the curves lie in a single or parallel planes. The relative motions are constrained to a single plane. Hence, the planar mechanism is a 2 – D mechanism.

3 .

In order to give the primary balance of the reciprocating parts of a multi-cylinder in-line engines,

A)

the algebraic sum of the primary forces must be equal to zero

B)

the algebraic sum of the couples about any point in the plane of the primary forces must be equal to zero

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

4 .

The gear train usually employed in clocks is a

A)

reverted gear train

B)

differential gear

C)

simple gear train

D)

sun and planet gear

Correct Answer : reverted gear train

5 .

A mass of 1 kg is attached to the end of a spring with a stiffness of 0.7 N/mm. The critical damping coefficient of this system is

A)

1.4 N-s/m

B)

18.52 N-s/m

C)

52.92 N-s/m

D)

529.2 N-s/m

Correct Answer : 52.92 N-s/m

6 .

If there are redundant constraints in the chain and it forms a statically indeterminate structure, what is the degree of freedom or the mobility of this structure?

A)

More than 0

B)

Less than 0

C)

1

D)

2

Correct Answer : Less than 0

Explanation : If n ≤-1, then there are redundant constraints in the chain and a statically indeterminate structure is formed. The structure is called a preloaded structure as some stress is created within the link so that it has negative mobility.

7 .

If the shortest link is fixed, what type of mechanism is obtained?

A)

Crank rocker mechanism

B)

Linkage is not planar

C)

Double rocker mechanism

D)

Double crank mechanism

Correct Answer : Double crank mechanism

Explanation : When the shortest link is fixed, the links adjacent to it rotate continuously and can be described as proper cranks. Thus, this mechanism is called a double crank mechanism.

8 .

The cam follower generally used in automobile engines is

A)

roller follower

B)

knife edge follower

C)

fiat faced follower

D)

spherical faced follower

Correct Answer : spherical faced follower

9 .

_________ mechanism is a crossed four bar chain mechanism in early steam engines to guide the piston rod in a cylinder to have an approximate straight line motion.

A)

Wattâ€™s

B)

Grasshopper

C)

Chebychevâ€™s

D)

Peaucellierâ€™s

Correct Answer : Wattâ€™s

Explanation : Watt’s mechanism is a four bar chain mechanism and was used by Watt in steam engines so as to guide the piston rod into a cylinder to have a straight line motion. Due to the rotation motion of the longer links, the centre of the shorter link traces an approximate straight line.

10 .

For a Whitworth quick return motion mechanism Î² = 110Â°. Find the ratio of time of cutting stroke to time of return stroke.

A)

0.42

B)

0.44

C)

2.27

D)

2.37

Correct Answer : 2.27

Explanation : Ratio of time of cutting stroke to time of return stroke for a Whitworth quick return motion mechanism = (360-β)/ β = (360-110)/110 = 2.27.

11 .

The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the

A)

pitch curve

B)

base circle

C)

pitch circle

D)

prime circle

Correct Answer : pitch curve

12 .

In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called

A)

maximum fluctuation of energy

B)

fluctuation of energy

C)

coefficient of fluctuation of energy

D)

None of the above

Correct Answer : fluctuation of energy

13 .

In a spring controlled governor, when the controlling force __________ as the radius of rotation increases, it is said to be a stable governor.

A)

increases

B)

decreases

C)

remains constant

D)

None of the above

Correct Answer : increases

14 .

The distance between the centre of suspension and centre of percussion is equal to the equivalent length of a simple pendulum.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

15 .

When the body is suspended at the point of suspension, its periodic time and frequency will be __________ as compared to the body suspended at the point of percussion.

A)

two times

B)

four times

C)

same

D)

None of the above

Correct Answer : same

16 .

Which of the following statement is correct?

A)

The D-slide valve is also called outside admission valve.

B)

The wear of the piston valve is less than the wear of the D-slide valve.

C)

The power absorbed in operating the piston valve is less than D-slide valve.

D)

All of the above

Correct Answer : All of the above

17 .

Critical damping is a function of

A)

mass and natural frequency

B)

mass and stiffness

C)

mass and damping coefficient

D)

damping coefficient and natural frequency

Correct Answer : mass and stiffness

18 .

In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done

A)

because of difficulty in manufacturing cam profile

B)

because of loose contact of follower with cam surface

C)

because the uniform velocity motion is a partial parabolic motion

D)

in order to have acceleration in beginning and retardation at the end of stroke within the finite limits

Correct Answer : in order to have acceleration in beginning and retardation at the end of stroke within the finite limits

19 .

The contact ratio for gears is

A)

zero

B)

infinity

C)

less than one

D)

greater than one

Correct Answer : greater than one

20 .

A governor is said to be stable, if the

A)

radius of rotation of balls increases as the equilibrium speed increases

B)

radius of rotation of balls decreases as the equilibrium speed increases

C)

radius of rotation of balls increases as the equilibrium speed decreases

D)

radius of rotation of balls decreases as the equilibrium speed decreases

Correct Answer : radius of rotation of balls increases as the equilibrium speed increases

21 .

In a Hartnell governor, the lift of the sleeve is given by (where r₁ and r₂ = Max. and min. radii of rotation, x = Length of ball arm of the lever, and y = Length of sleeve arm of the lever)

A)

(r₁ + r₂) y/x

B)

(r₁ + r₂) x/y

C)

(r₁ - r₂) y/x

D)

(r₁ - r₂) x/y

Correct Answer : (r₁ - r₂) y/x

22 .

When a mechanism is required to transmit power or to do some particular type of work, then it becomes a machine.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

23 .

The transmissibility, for all values of damping factor, will be less than unity, if Ï‰/Ï‰n is

A)

equal to 1

B)

less than âˆš2

C)

equal to âˆš2

D)

greater than âˆš2

Correct Answer : greater than âˆš2

24 .

For the brake to be self locking, the force P at C shown in the below figure, should

A)

be zero

B)

act in upward direction

C)

act in downward direction

D)

None of the above

Correct Answer : be zero

25 .

In a four bar chain or quadric cycle chain

A)

each of the four pairs is a turning pair

B)

one is a turning pair and three are sliding pairs

C)

two are turning pairs and two are sliding pairs

D)

three are turning pairs and one is a sliding pair

Correct Answer : each of the four pairs is a turning pair

26 .

The ratio of the number of teeth to the pitch circle diameter in millimetres, is called

A)

module

B)

circular pitch

C)

diametral pitch

D)

None of the above

Correct Answer : diametral pitch

27 .

The rotating shafts tend to vibrate violently at whirling speeds because

A)

the system is unbalanced

B)

resonance is caused due to the heavy mass of the rotor

C)

bearing centre line coincides with the axis

D)

the shafts are rotating at very high speeds

Correct Answer : resonance is caused due to the heavy mass of the rotor

28 .

Which of the following is an inversion of a double slider crank chain?

A)

Oldham's coupling

B)

Elliptical trammel

C)

Scotch yoke mechanism

D)

All of the above

Correct Answer : All of the above

29 .

The unbalanced force due to revolving masses

A)

varies in direction but constant in magnitude

B)

varies in magnitude and direction both

C)

constant in magnitude and direction both

D)

varies in magnitude but constant in direction

Correct Answer : varies in direction but constant in magnitude

30 .

Which of these is not a type of clutch?

A)

Conical

B)

Centrifugal

C)

Cylindrical

D)

Single disc

Correct Answer : Cylindrical

Explanation : Single disc, conical and centrifugal are types of clutches. Clutches are used for the transmission of power in shafts and machines which are started and stopped frequently. It is also used to deliver power to the machine which are partially or fully loaded.

31 .

In a disc clutch, if there are n1 number of discs on the driving shaft and n2 number of discs on the driven shaft, then the number of pairs of contact surfaces will be

A)

n1 + n2

B)

n1 + n2 - 1

C)

n1 + n2 + 1

D)

n1 + n2 - 2

Correct Answer : n1 + n2 - 1

32 .

The effect of swaying couple in a locomotive is resisted by the side pressure between the flanges of the tyres of the wheel and the inside of the rails.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

33 .

The Klein's diagram is useful to find

A)

velocity of various parts

B)

acceleration of various parts

C)

displacement of various parts

D)

angular acceleration of various parts

Correct Answer : acceleration of various parts

34 .

The pitching of a ship produces forces on the bearings which act __________ to the motion of the ship.

A)

vertically and parallel

B)

horizontally and parallel

C)

vertically and perpendicular

D)

horizontally and perpendicular

Correct Answer : horizontally and perpendicular

35 .

At the node, the shaft remains unaffected by the vibration.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

36 .

The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ωâ‚ rad/s in the clockwise direction and the link OB turns with angular velocity ωâ‚‚ rad/s in the anti-clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)

A)

ωâ‚.ωâ‚‚.r

B)

( ωâ‚ - ωâ‚‚)r

C)

( ωâ‚ + ωâ‚‚)r

D)

( ωâ‚ - ωâ‚‚)2r

Correct Answer : ( ωâ‚ + ωâ‚‚)r

37 .

When the two elements of a pair have __________ when in motion, it is said to a lower pair.

A)

line or point contact

B)

surface contact

C)

Both (A) and (B)

D)

None of the above

Correct Answer : surface contact

38 .

The ratio of maximum fluctuation of energy to the workdone per cycle is called

A)

fluctuation of energy

B)

maximum fluctuation of energy

C)

coefficient of fluctuation of energy

D)

None of the above

Correct Answer : coefficient of fluctuation of energy

39 .

In a steam engine, the earlier cut-off with a simple slide valve may be obtained by increasing the steam lap and the angle of advance of the eccentric but keeping constant the travel and lead of the valve, This method will

A)

cause withdrawing or throttling of steam

B)

reduce maximum opening of port to steam

C)

reduce length of effective stroke of piston

D)

All of the above

Correct Answer : reduce maximum opening of port to steam

40 .

The size of cam depends upon

A)

pitch curve

B)

pitch circle

C)

prime circle

D)

base circle

Correct Answer : base circle

41 .

Which of the following statement is correct?

A)

The primary unbalanced force is maximum twice in one revolution of the crank.

B)

The primary unbalanced force is less than the secondary unbalanced force.

C)

The unbalanced force due to reciprocating masses varies in magnitude and direction both.

D)

The magnitude of swaying couple in locomotives is inversely proportional to the distance between the two cylinder centre lines

Correct Answer : The primary unbalanced force is maximum twice in one revolution of the crank.

42 .

The magnitude of velocities of the points on a rigid link is

A)

directly proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre

B)

directly proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre

C)

inversely proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre

D)

inversely proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre

Correct Answer : inversely proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre

43 .

A pendulum type governor is a Watt governor.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

44 .

In a single slider crank chain

A)

one is a turning pair and three are sliding pairs

B)

two are turning pairs and two are sliding pairs

C)

three are turning pairs and one is a sliding pair

D)

each of the four pairs is a turning pair

Correct Answer : three are turning pairs and one is a sliding pair

45 .

The mechanism consisting of three turning pairs and one sliding pair, is called a

A)

single slider crank chain

B)

Whitworth quick return motion mechanism

C)

crank and slotted lever quick return motion mechanism

D)

All of the above

Correct Answer : All of the above

46 .

According to Kennedy's theorem, if three bodies move relatively to each other, their instantaneous centres will lie on a

A)

triangle

B)

rectangle

C)

straight line

D)

parabolic curve

Correct Answer : straight line

47 .

The tangential component of acceleration of the slider with respect to the coincident point on the link is called coriolis component of acceleration.

A)

Agree

B)

Disagree

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Agree

48 .

The periodic time is given by (where Ï‰ = Angular velocity of the particle in rad/s)

A)

Ï€/Ï‰

B)

2Ï€/Ï‰

C)

Ï‰/2Ï€

D)

Ï‰ x 2Ï€

Correct Answer : 2Ï€/Ï‰

49 .

When two links are connected by a pin joint, their instantaneous centre lies

A)

at the centre of circle

B)

on their point of contact

C)

at the centre of curvature

D)

at the pin joint

Correct Answer : at the pin joint

50 .

The dedendum circle diameter is equal to (where Ï† = Pressure angle)

A)

pitch circle dia. x sin Ï†

B)

pitch circle dia. x cos Ï†

C)

addendum circle dia. x cos Ï†

D)

clearance circle dia. x cos Ï†

Correct Answer : pitch circle dia. x cos Ï†

51 .

The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as

A)

damping factor

B)

damping coefficient

C)

magnification factor

D)

logarithmic decrement

Correct Answer : magnification factor

52 .

The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (Î¸) is equal to

A)

0Â° and 90Â°

B)

90Â° and 180Â°

C)

135Â° and 315Â°

D)

270Â° and 360Â°

Correct Answer : 90Â° and 180Â°

53 .

A point on a connecting link (excluding end points) of a double slider crank mechanism traces a

A)

elliptical path

B)

parabolic path

C)

hyperbolic path

D)

straight line path

Correct Answer : elliptical path

54 .

If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be

A)

same as the first one

B)

four times the first one

C)

one fourth of the first one

D)

one and a half times the first one

Correct Answer : same as the first one

55 .

The Grubler's criterion for determining the degrees of freedom (n) of a mechanism having plane motion is (where l = Number of links, and j = Number of binary joints)

A)

n = (l - 1) - j

B)

n = 2(l - 1) - 2j

C)

n = 3(l - 1) - 2j

D)

n = 4(l - 1) - 3j

Correct Answer : n = 3(l - 1) - 2j

56 .

The included angle for the V-belt is usually

A)

60Â° to 80Â°

B)

30Â° to 40Â°

C)

20Â° to 30Â°

D)

10Â° to 20Â°

Correct Answer : 30Â° to 40Â°

57 .

In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be

A)

isochronous

B)

unaffected of sensitivity

C)

more sensitive

D)

less sensitive

Correct Answer : less sensitive

58 .

In a multi plate clutch, the formula for T is given by ______

A)

n.Âµ.W.R

B)

n.Âµ.W.r1

C)

n.Âµ.W.r2

D)

n.Âµ.W.(r1+r2)

Correct Answer : n.Âµ.W.R

Explanation : In a multi plate clutch, the formula for T is given by n.µ.W.R

The formula is the same for torque in a single plate clutch. But for large amount of torque to be transmitted, multi plate clutch is used. Multi plate clutches are used in motor vehicles and machine tools.

59 .

In a conical clutch, the mean radius of the bearing surface is 300 mm whereas the breadth is 20 mm. Find the inner and outer radii. The semi cone angle is 30Â°.

A)

160 mm, 140 mm

B)

155 mm, 145 mm

C)

145 mm, 155 mm

D)

140 mm, 160 mm

Correct Answer : 155 mm, 145 mm

Explanation : In a conical clutch b sinα = r1 – r2
r1 – r2 = 10 and r1 + r2 = 300
r1 = 155 mm and r2 = 145 mm.

60 .

If the outer and inner radius of the contact surfaces are 100 mm and 75 mm respectively and the semi cone angle is 22.5Â°, find the value of the face width required.

A)

23.87 mm

B)

65.33 mm

C)

78.94 mm

D)

89.43 mm

Correct Answer : 65.33 mm

Explanation : In a conical clutch b sinα = r1 – r2
b x sin 22.5° = 100 – 75
b = 65.33 mm.

61 .

The smaller and generally the driving gear of a pair of mated gears is called _________

A)

rack

B)

pitch

C)

pinion

D)

module

Correct Answer : pinion

Explanation : Pinion is the smaller and the driving gear of a pair of mated gears. It is used in gear train drives and is usually the smaller gear. The pinion engages the larger gear or rack that helps in the turning of the wheels of the vehicle.

62 .

The distance measured along the circumference of the pitch circle from a point on one tooth to the same point on the adjacent tooth is called ________

A)

pitch point

B)

pitch diameter

C)

line of centers

D)

circular pitch

Correct Answer : circular pitch

Explanation : Circular pitch is the distance measured along the circumference of the pitch circle from a point on one tooth to the same point on the adjacent tooth. So basically, it is the distance between corresponding points of consecutive gear teeth.

p = d π/ N; where, p is the circular pitch, d is the standard pitch diameter and N is the number of teeth.

63 .

In order to balance the reciprocating masses,

A)

primary forces and couples must be balanced

B)

secondary forces and couples must be balanced

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

64 .

In a screw jack, the effort required to lower the load W is given by

A)

P = W tan(Ï† - Î±)

B)

P = W tan(Î± - Ï†)

C)

P = W tan(Î± + Ï†)

D)

P = W cos(Î± + Ï†)

Correct Answer : P = W tan(Ï† - Î±)

65 .

An automobile steering gear is an example of

A)

higher pair

B)

lower pair

C)

sliding pair

D)

rolling pair

Correct Answer : lower pair

66 .

The static friction______.

A)

is independent of the area of contact, between the two surfaces

B)

bears a constant ratio to the normal reaction between the two surfaces

C)

always acts in a direction, opposite to that in which the body tends to move

D)

All of the above

Correct Answer : All of the above

67 .

In a gear having involute teeth, the normal to the involute is a tangent to the

A)

base circle

B)

pitch circle

C)

addendum circle

D)

dedendum circle

Correct Answer : base circle

68 .

A body is said to be under forced vibrations, when

A)

a body vibrates under the influence of external force

B)

no external force acts on a body, after giving it an initial displacement

C)

there is a reduction in amplitude after every cycle of vibration

D)

None of the above

Correct Answer : there is a reduction in amplitude after every cycle of vibration

69 .

The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft, and tan Ï† = Coefficient of friction between the shaft and bearing)

A)

r sin Ï†

B)

r cos Ï†

C)

r tan Ï†

D)

r/2 cos Ï†

Correct Answer : r sin Ï†

70 .

The primary unbalanced force is maximum __________ in one revolution of the crank.

A)

twice

B)

four times

C)

eight times

D)

sixteen times

Correct Answer : twice

71 .

The instantaneous centres which vary with the configuration of mechanism, are called

A)

fixed instantaneous centres

B)

permanent instantaneous centres

C)

neither fixed nor permanent instantaneous centres

D)

None of the above

Correct Answer : neither fixed nor permanent instantaneous centres

72 .

If the damping factor for a vibrating system is unity, then the system will be

A)

over damped

B)

critically damped

C)

under damped

D)

without vibrations

Correct Answer : critically damped

73 .

When a point at the end of a link moves with constant angular velocity, its acceleration will have

A)

coriolis component only

B)

radial component only

C)

tangential component only

D)

radial and tangential components both

Correct Answer : radial component only

74 .

When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as

A)

compound pendulum

B)

simple pendulum

C)

second's pendulum

D)

torsional pendulum

Correct Answer : compound pendulum

75 .

Longitudinal vibrations are said to occur when the particles of a body moves

A)

perpendicular to its axis

B)

in a circle about its axis

C)

parallel to its axis

D)

None of the above

Correct Answer : parallel to its axis

76 .

The velocity of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by (where Ï‰ = Angular velocity of the cam shaft)

A)

Ï‰(râ‚ - râ‚‚)sin Î¸

B)

Ï‰(râ‚ - râ‚‚)cos Î¸

C)

Ï‰(râ‚ + râ‚‚)cos Î¸ cosecÂ² Î¸

D)

Ï‰(râ‚ + râ‚‚)sinÎ¸ secÂ²Î¸

Correct Answer : Ï‰(râ‚ + râ‚‚)sinÎ¸ secÂ²Î¸

77 .

The sensitiveness of the governor __________ as the speed range decreases.

A)

increases

B)

decreases

C)

remains unaffected

D)

None of the above

Correct Answer : decreases

78 .

In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from

A)

50Â° - 60Â°

B)

60Â° - 70Â°

C)

70Â° - 80Â°

D)

80Â° - 90Â°

Correct Answer : 80Â° - 90Â°

79 .

The secondary unbalanced force is maximum __________ in one revolution of the crank.

A)

two times

B)

four times

C)

eight times

D)

sixteen times

Correct Answer : four times

80 .

A spring controlled governor is found unstable. It can be made stable by

A)

increasing the ball mass

B)

decreasing the ball mass

C)

decreasing the spring stiffness

D)

increasing the spring stiffness

Correct Answer : decreasing the spring stiffness

81 .

In order to double the period of a simple pendulum, the length of the string should be

A)

halved

B)

doubled

C)

quadrupled

D)

None of the above

Correct Answer : quadrupled

82 .

The frictional torque transmitted by a cone clutch is same as that of

A)

flat pivot bearing

B)

flat collar bearing

C)

conical pivot bearing

D)

truncated conical pivot bearing

Correct Answer : truncated conical pivot bearing

83 .

When the elements of a pair are kept in contact by the action of external forces, the pair is said to be a

A)

lower pair

B)

higher pair

C)

force-closed pair

D)

self-closed pair

Correct Answer : self-closed pair

84 .

The centrifugal tension in belts

A)

increases power transmitted

B)

have no effect on power transmitted

C)

decreases power transmitted

D)

increases power transmitted upto a certain speed and then decreases

Correct Answer : have no effect on power transmitted

85 .

In a Hartnell governor, the compression of the spring is __________ the lift of the sleeve.

A)

equal to

B)

less than

C)

greater than

D)

None of the above

Correct Answer : equal to

86 .

In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.

A)

equal to

B)

independent of

C)

inversely proportional to

D)

directly proportional to

Correct Answer : inversely proportional to

87 .

A body in motion will be subjected to coriolis acceleration when that body is

A)

in plane rotation with variable velocity

B)

in plane translation with variable velocity

C)

restrained to rotate while sliding over another body

D)

in plane motion which is a resultant of plane translation and rotation

Correct Answer : restrained to rotate while sliding over another body

88 .

The rolling of a complete ship side-ways is known as pitching of a ship.

A)

True

B)

False

C)

Can not say

D)

Neither (A) nor (B)

Correct Answer : False

89 .

The frictional torque transmitted by a disc or plate clutch is same as that of

A)

flat pivot bearing

B)

flat collar bearing

C)

conical pivot bearing

D)

truncated conical pivot bearing

Correct Answer : flat collar bearing

90 .

In the below figure, PC is the connecting rod and OC is the crank making an angle θ with the line of stroke PO and rotates with uniform angular velocity at ω rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral C Q NO, if N coincides with O, then

A)

acceleration and velocity of the piston P is zero

B)

acceleration and velocity of the piston P is maximum

C)

acceleration of the piston P is zero and its velocity is maximum

D)

acceleration of the piston P is maximum and its velocity is zero

Correct Answer : acceleration of the piston P is zero and its velocity is maximum

91 .

When there is a reduction in amplitude over every cycle of vibration, then the body is said to have

A)

damped vibration

B)

free vibration

C)

forced vibration

D)

under damped vibration

Correct Answer :

92 .

The magnitude of linear velocity of a point B on a link AB relative to point A is (where Ï‰ = Angular velocity of the link AB)

A)

Ï‰ x AB

B)

Ï‰ (AB)Â²

C)

Ï‰2 x AB

D)

(Ï‰ x AB)Â²

Correct Answer : Ï‰ x AB

93 .

A slender shaft supported on two bearings at its ends carries a disc with an eccentricity e from the axis of rotation. The critical speed of the shaft is Nc. If the disc is replaced by a second one of same mass but mounted with an eccentricily 2 e, then the critical speed of the shaft in the second case is

A)

Nc

B)

2 Nc

C)

Nc/2

D)

Nc/√2

Correct Answer : Nc/√2

94 .

The mechanism in which two are turning pairs and two are sliding pairs, is called a

A)

elliptical trammel

B)

Scotch yoke mechanism

C)

double slider crank chain

D)

All of the above

Correct Answer : All of the above

95 .

In a multiple V-belt drive, all the belts should stretch at the same rate.

A)

Agree

B)

Disagree

C)

Can not say

D)

Neither (A) nor (B)

Correct Answer : Agree

96 .

In a reciprocating engine, usually __________ of the reciprocating masses are balanced.

A)

one-half

B)

two-third

C)

three-fourth

D)

Whole

Correct Answer : two-third

97 .

The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by

A)

Ï‰â‚‚râ‚ sin Î¸

B)

Ï‰â‚‚R cos Î¸

C)

Ï‰â‚‚(R - râ‚)cos Î¸

D)

Ï‰â‚‚(R - râ‚)sin Î¸

Correct Answer : Ï‰â‚‚(R - râ‚)cos Î¸

98 .

The mechanism forms a structure, when the number of degrees of freedom (n) is equal to

A)

0

B)

1

C)

2

D)

-1

Correct Answer : 0

99 .

The sense of coriolis component 2 Ï‰v is same as that of the relative velocity vector v rotated at

A)

180Â° in the direction opposite to the rotation of the link containing the path

B)

90Â° in the direction of rotation of the link containing the path

C)

45Â° in the direction of rotation of the link containing the path

D)

45Â° in the direction opposite to the rotation of the link containing the path

Correct Answer : 90Â° in the direction of rotation of the link containing the path

100 .

The condition for correct steering of a Davis steering gear is (where Î± = Angle of inclination of the links to the vertical)

A)

sin Î± = b/c

B)

cos Î± = c/b

C)

tan Î± = c/2b

D)

cot Î± = c/2b

Correct Answer : tan Î± = c/2b

101 .

The centre of percussion is below the centre of gravity of the body and is at a distance equal to

A)

hÂ²/kG

B)

kGÂ²/h

C)

h/kG

D)

h x kG

Correct Answer : kGÂ²/h

102 .

The axis of precession is __________ to the plane in which the axis of spin is going to rotate.

A)

parallel

B)

perpendicular

C)

Both (A) and (B)

D)

None of the above

Correct Answer : perpendicular

103 .

Bifilar suspension method is used to find the

A)

moment of inertia of the body

B)

periodic time of the body

C)

angular acceleration of the body

D)

frequency of vibration of the body

Correct Answer : moment of inertia of the body

104 .

The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as

A)

incompletely constrained motion

B)

successfully constrained motion

C)

Both (A) and (B)

D)

completely constrained motion

Correct Answer : completely constrained motion

105 .

The motion of a shaft in a circular hole is an example of

A)

completely constrained motion

B)

successfully constrained motion

C)

incompletely constrained motion

D)

None of the above

Correct Answer : incompletely constrained motion

106 .

A spring controlled governor is said to be unstable when the controlling force

A)

remains constant for all radii of rotation

B)

increases as the radius of rotation decreases

C)

decreases as the radius of rotation increases

D)

increases as the radius of rotation increases

Correct Answer : decreases as the radius of rotation increases

107 .

Balancing of rotating and reciprocating parts of an engine is necessary when it runs at

A)

slow speed

B)

highs peed

C)

moderate speed

D)

any one of these

Correct Answer : highs peed

108 .

When the nature of contact between the elements of a pair is such that one element can turn about the other by screw threads, the pair is known as a

A)

screw pair

B)

turning pair

C)

sliding pair

D)

spherical pair

Correct Answer : screw pair

109 .

In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as

A)

hammer blow

B)

tractive force

C)

swaying couple

D)

None of the above

Correct Answer : tractive force

110 .

The angle turned by the gear from the beginning to the end of engagement of a pair of teeth is called ___________

A)

angle of action

B)

angle of recess

C)

angle of approach

D)

angle of contact

Correct Answer : angle of contact

Explanation : Angle of action is the angle turned by the gear from the beginning to the end of engagement of a pair of teeth. Angle of action = Arc of contact / r; where r is the radius of the pinion.

111 .

The condition which must be fulfilled by two gear tooth profiles to maintain a constant angular velocity ratio between them is called ________

A)

interference

B)

arc of contact

C)

law of gearing

D)

path of contact

Correct Answer : law of gearing

Explanation : Law of gearing is the condition which must be fulfilled by two gear tooth profiles to maintain a constant angular velocity ratio between them. In order to maintain this constant angular velocity, the common normal of the tooth profiles should always pass through a fixed point on the line of centres, called fixed point.

112 .

Velocity of sliding at the pitch point = (Ï‰p + Ï‰g) x _____________

A)

0

B)

path of recess

C)

path of contact

D)

arc of approach

Correct Answer : 0

Explanation : At the pitch point, there is no relative motion between the gears. Thus, the velocity of sliding is 0. Velocity of sliding at the pitch point = (ωp + ωg) x 0 = 0.

113 .

The distance travelled by a point on either pitch circle of the two wheels during the period of contact of a pair of teeth is called _____

A)

contact ratio

B)

arc of contact

C)

angle of action

D)

path of contact

Correct Answer : arc of contact

Explanation : The arc of contact is defined as the distance travelled by a point on either pitch circle of the two wheels during the period of contact of a pair of teeth. Simply, it is traced out along the pitch circle while one pair of the teeth is in contact.

114 .

Which of the following is an example of sliding pair?

A)

Ball and a socket joint

B)

Piston and cylinder of a reciprocating steam engine

C)

Lead screw of a lathe with nut

D)

Shaft with collars at both ends fitted into a circular hole

Correct Answer : Piston and cylinder of a reciprocating steam engine

115 .

The coriolis component of acceleration exists whenever apoint moves along a path that has

A)

rotational motion

B)

linear displacement

C)

tangential acceleration

D)

gravitational acceleration

Correct Answer : rotational motion

116 .

In a steam engine, the distance by which the inner edge of the D-slide valve overlaps the steam port is called lead.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Disagree

117 .

The distance by which the __________ of the D-slide valve overlaps the steam port is called exhaust lap.

A)

inner edge

B)

outer edge

C)

Both (A) and (B)

D)

None of the above

Correct Answer : inner edge

118 .

The stress induced in a body will be shear stress, when it is subjected to

A)

transverse vibrations

B)

longitudinal vibrations

C)

torsional vibrations

D)

None of the above

Correct Answer : torsional vibrations

119 .

A machine mounted on a single coil spring has a period of free vibration of tp . If the spring is cut into four equal parts and placed in parallel and the machine is mounted on them, then the period of free vibration of the new system will become

A)

4 tp

B)

16 tp

C)

tp/16

D)

tp/4

Correct Answer : tp/4

120 .

If the number of links in a mechanism are equal to l, then the number of possible inversions are equal to

A)

l - 2

B)

l - 1

C)

l + 1

D)

l

Correct Answer : l

121 .

Effort of a governor is the

A)

workdone at the sleeve for maximum equilibrium speed

B)

mean force exerted at the sleeve for maximum equilibrium speed

C)

Both (A) and (B)

D)

mean force exerted at the sleeve for a given percentage change of speed

Correct Answer : mean force exerted at the sleeve for a given percentage change of speed

122 .

The pressure angle for involute gears depends upon the size of teeth.

A)

Right

B)

Wrong

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Wrong

123 .

The motion between a pair which takes place in __________ is known as incompletely constrained motion.

A)

one direction only

B)

more than one direction

C)

Can not say

D)

None of the above

Correct Answer : more than one direction

124 .

When the primary direct crank of a reciprocating engine makes an angle of Î¸ with the line of stroke, then the secondary direct crank will make an angle of __________ with the line of stroke.

A)

Î¸

B)

Î¸/2

C)

2 Î¸

D)

4 Î¸

Correct Answer : 2 Î¸

125 .

Which of the following is a pendulum type governor?

A)

Watt governor

B)

Porter governor

C)

Hartnell governor

D)

None of the above

Correct Answer : Watt governor

126 .

The angle of inclination of the plane, at which the body begins to move down the plane is called

A)

angle of repose

B)

angle of friction

C)

angle of projection

D)

None of the above

Correct Answer : angle of repose

127 .

The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in

A)

torsional vibrations

B)

transverse vibrations

C)

longitudinal vibrations

D)

All of the above

Correct Answer : All of the above

128 .

The centre of gravity of a coupler link in a four bar mechanism will experience

A)

no acceleration

B)

only linear acceleration

C)

only angular acceleration

D)

both linear and angular acceleration

Correct Answer : both linear and angular acceleration

129 .

Which of the following governor is used to drive a gramophone?

A)

Watt governor

B)

Porter governor

C)

Pickering governor

D)

Hartnell governor

Correct Answer : Pickering governor

130 .

In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to

A)

have perfect balancing

B)

to start the locomotive quickly

C)

minimise the effect of primary forces

D)

minimise the effect of secondary forces

Correct Answer : minimise the effect of secondary forces

131 .

A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the

A)

radius of journal

B)

angular velocity of journal

C)

magnitude of the forces on journal

D)

clearance between journal and bearing

Correct Answer : angular velocity of journal

132 .

The relation between the controlling force (Fc) and radius of rotation (r) for a stable spring controlled governor is

A)

Fc = ar - b

B)

Fc = ar

C)

Fc = ar +b

D)

Fc = a/r + b

Correct Answer : Fc = ar - b

133 .

A rotary internal combustion engine has __________ cylinders.

A)

four

B)

five

C)

six

D)

seven

Correct Answer : seven

134 .

The power transmitted by a belt is maximum when the maximum tension in the belt is __________ of centrifugal tension.

A)

one-third

B)

two-third

C)

three times

D)

None of the above

Correct Answer : three times

135 .

The component of the acceleration, perpendicular to the velocity of the particle, at the given instant is called

A)

coriolis component

B)

radial component

C)

tangential component

D)

None of the above

Correct Answer : radial component

136 .

Pitch point of a cam is

A)

any point on the pitch curve

B)

any point on the pitch circle

C)

a point on the pitch curve having minimum pressure angle

D)

a point on the pitch curve having maximum pressure angle

Correct Answer : a point on the pitch curve having maximum pressure angle

137 .

A torsional system with discs of moment of inertia I1 and I2 as shown in the below figure, is gear driven such that the ratio of speed of shaft B to shaft A is 'G'. Neglecting the inertia of gears, the equivalent inertia of disc on shaft B at the speed of shaft A is equal to

A)

G.Iâ‚‚

B)

Iâ‚‚/G

C)

G².Iâ‚‚

D)

Iâ‚‚/G²

Correct Answer : G².Iâ‚‚

138 .

A spring controlled governor is said to be isochronous when the controlling force

A)

remains constant for all radii of rotation

B)

increases as the radius of rotation decreases

C)

increases as the radius of rotation increases

D)

decreases as the radius of rotation increases

Correct Answer : remains constant for all radii of rotation

139 .

In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve is by increasing the angle of advance of the eccentric while the throw of the eccentric, steam lap and exhaust lap are kept constant. This method will

A)

cause withdrawing or throttling of steam

B)

reduce length of effective stroke of piston

C)

reduce maximum opening of port to steam

D)

All of the above

Correct Answer : reduce length of effective stroke of piston

140 .

The critical speed of a shaft depends upon its

A)

mass

B)

stiffness

C)

mass and stiffness

D)

stiffness and eccentricity

Correct Answer : mass and stiffness

141 .

Which of the following mechanism is an approximate straight line motion mechanism?

A)

Watt's mechanism

B)

Robert's mechanism

C)

Grasshopper mechanism

D)

All of the above

Correct Answer : All of the above

142 .

A shaft carrying two rotors at its ends will have

A)

no node

B)

one node

C)

two nodes

D)

three nodes

Correct Answer : one node

143 .

When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will

A)

oscillate with constant amplitude

B)

oscillate with decreasing amplitude

C)

oscillate with increasing time period

D)

return to equilibriumposition without oscillation

Correct Answer : oscillate with increasing time period

144 .

A mechanism consisting of four links is called a __________ mechanism.

A)

simple

B)

compound

C)

Both (A) and (B)

D)

None of the above

Correct Answer : simple

145 .

The amplitude of vibration is always __________ the radius of the circle.

A)

less than

B)

greater than

C)

equal to

D)

None of the above

Correct Answer : equal to

146 .

An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the

A)

tip of both gear and pinion

B)

flanks of both gear and pinion

C)

tip of the pinion and flank of gear

D)

tip of the gear tooth and flank of pinion

Correct Answer : tip of the gear tooth and flank of pinion

147 .

In vibration isolation system, if Ï‰/Ï‰n > 1, then the phase difference between the transmitted force and the disturbing force is

A)

270Â°

B)

180Â°

C)

90Â°

D)

0Â°

Correct Answer : 180Â°

148 .

Which of the following is an inversion of a single slider crank chain?

A)

Pendulum pump

B)

Oscillating cylinder engine

C)

Rotary internal combustion engine

D)

All of the above

Correct Answer : All of the above

149 .

In a radial cam, the follower moves

A)

in a direction perpendicular to the cam axis

B)

in a direction parallel to the cam axis

C)

along the cam axis

D)

in any direction irrespective of the cam axis

Correct Answer : in a direction perpendicular to the cam axis

150 .

The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.

A)

same

B)

different

C)

Both (A) and (B)

D)

None of the above

Correct Answer : same

151 .

Which of the following is a turning pair?

A)

Ball and a socket joint

B)

Lead screw of a lathe with nut

C)

Piston and cylinder of a reciprocating steam engine

D)

Shaft with collars at both ends fitted into a circular hole

Correct Answer : Shaft with collars at both ends fitted into a circular hole

152 .

In a simple train of wheels, the velocity ratio __________ the intermediate wheels.

A)

depends upon

B)

is independent of

C)

Can not say

D)

None of the above

Correct Answer : is independent of

153 .

The two elements of a pair are said to form a higher pair, when they

A)

permit relative motion

B)

have a line or point contact when in motion

C)

have a surface contact when in motion

D)

are kept in contact by the action of external forces, when in motion

Correct Answer : have a line or point contact when in motion

154 .

The maximum fluctuation of energy is the

A)

sum of the maximum and minimum energies

B)

ratio of the mean resisting torque to the workdone per cycle

C)

difference between the maximum and minimum energies

D)

variations of energy above and below the mean resisting torque line

Correct Answer : difference between the maximum and minimum energies

155 .

The method of obtaining different mechanisms by fixing in turn different links in a kinematic chain, is known as

A)

machine

B)

structure

C)

inversion

D)

compound mechanism

Correct Answer : inversion

Explanation : Contact ratio is the of the arc od contact to the circular pitch. The number of teeth in contact = arc of contact / circular pitch = path of contact / (circular pitch x cos φ).

156 .

The contact ratio is the ratio of arc of contact to the ________

A)

module

B)

dedendum

C)

Both (A) and (B)

D)

circular pitch

Correct Answer : circular pitch

157 .

When large gear reductions are needed _________ gears are used.

A)

worm

B)

spur

C)

bevel

D)

helical

Correct Answer : worm

Explanation : Worm gears are used where large speed reductions are needed. The horizontal portion of the gear is called as a worm and the assembly of it with the gear is known as a worm gear. Worm can easily turn a gear but a gear cannot turn a worm because of the shallow angle on the worm.

158 .

Which of the following is an advantage of worm gear?

A)

It is expensive

B)

Used for reducing speed and increasing torque

C)

Produce a lot of heat

D)

Has high power losses and low transmission efficiency

Correct Answer : Used for reducing speed and increasing torque

Explanation : Reduction of speed and increasing the torque is an advantage of worm gear. The rest are the disadvantages of the worm gear. Worm gears are used in gate control mechanisms, hoisting machines, automobile steering mechanisms, lifts, conveyors and presses.

159 .

The distance by which a helix advances along the axis of the gear for one turn around is called __________

A)

joint line

B)

lead

C)

axial pitch

D)

normal link

Correct Answer : lead

Explanation : Lead is the distance by which a helix advances along the axis of the gear for one turn around. The axial pitch is equal to the lead in a single helix and the axial pitch is one half of the lead in a double helix and so on.

160 .

Bevel gears are equivalent to rolling _______

A)

cubes

B)

cuboids

C)

cones

D)

spheres

Correct Answer : cones

Explanation : By geometry of bevel gears, it is evident that they are equivalent to rolling cones. Their pitch surface is a cone. Bevel gears exist as pairs which can be either straight or inclined at different angles.

161 .

Which of the gears has the highest contact ratio?

A)

Spur

B)

Worm

C)

Helical

D)

Bevel

Correct Answer : Bevel

Explanation : Bevel gears increase the contact ratio. It avoids interference and results in stronger pinion teeth. The gear ratio can be determined from the number of teeth, pitch diameters or pitch cone angles.

162 .

The static friction

A)

is independent of the area of contact, between the two surfaces

B)

bears a constant ratio to the normal reaction between the two surfaces

C)

always acts in a direction, opposite to that in which the body tends to move

D)

All of the above

Correct Answer : is independent of the area of contact, between the two surfaces

163 .

The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (Î¸) is equal to

A)

90Â° and 180Â°

B)

45Â° and 225Â°

C)

180Â° and 270Â°

D)

270Â° and 360Â°

Correct Answer : 45Â° and 225Â°

164 .

The gears are termed as medium velocity gears, if their peripheral velocity is

A)

1 - 3 m/s

B)

3 - 15 m/s

C)

15 - 30 m/s

D)

30 - 50 m/s

Correct Answer : 3 - 15 m/s

165 .

For a twin cylinder V-engine, the crank positions for primary reverse cranks and secondary direct cranks are shown in the below figure. The engine is a

A)

30° V-engine

B)

60° V-engine

C)

120° V-engine

D)

150° V-engine

Correct Answer : 30° V-engine

166 .

The frequency of damped vibrations with viscous damping is __________ the frequency of undamped vibrations.

A)

same as

B)

more than

C)

less than

D)

None of the above

Correct Answer : less than

167 .

Whitworth quick return motion mechanism consists of three turning pairs and one sliding pair.

A)

Right

B)

Wrong

C)

Can not say

D)

None of the above

Correct Answer : Right

168 .

The dynamic friction is the friction experienced by a body, when the body

A)

is in motion

B)

is at rest

C)

just begins to slide over the surface of the other body

D)

None of the above

Correct Answer : is in motion

169 .

The steering of a ship means

A)

movement of a complete ship up and down in vertical plane about transverse axis

B)

rolling of a complete ship side-ways

C)

turning of a complete ship in a curve towards right or left, while it moves forward

D)

None of the above

Correct Answer : turning of a complete ship in a curve towards right or left, while it moves forward

170 .

The radial distance of a tooth from the pitch circle to the bottom of the tooth is called

A)

addendum

B)

dedendum

C)

clearance

D)

working depth

Correct Answer : dedendum

171 .

When the crank is at the inner dead centre, in a reciprocating steam engine, then the velocity of the piston will be

A)

zero

B)

minimum

C)

maximum

D)

None of the above

Correct Answer : zero

172 .

In under damped vibrating system, the amplitude of vibration

A)

decreases linearly with time

B)

increases linearly with time

C)

increases exponentially with time

D)

decreases exponentially with time

Correct Answer : decreases exponentially with time

173 .

In vibration isolation system, the transmissibility will be equal to unity, for all values of damping factor, if Ï‰/Ï‰n is

A)

equal to one

B)

less than âˆš2

C)

equal to âˆš2

D)

greater than âˆš2

Correct Answer : equal to âˆš2

174 .

The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ωâ‚ rad/s in the clockwise direction and the link OB turns with angular velocity ωâ‚‚ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)

A)

ωâ‚.ωâ‚‚.r

B)

( ωâ‚ - ωâ‚‚)r

C)

( ωâ‚ + ωâ‚‚)r

D)

( ωâ‚ - ωâ‚‚)2r

Correct Answer : ( ωâ‚ - ωâ‚‚)r

175 .

In railway axle boxes, the bearing used is

A)

double row spherical roller bearing

B)

deep groove ball bearing

C)

cylindrical roller bearing

D)

double row self-aligning ball bearing

Correct Answer : double row spherical roller bearing

176 .

The pair is known as a higher pair, when the relative motion between the elements of a pair is

A)

turning only

B)

rolling only

C)

sliding only

D)

partly turning and partly sliding

Correct Answer : partly turning and partly sliding

177 .

When the connection between the two elements is such that only required kind of relative motion occurs, it is known as self-closed pair.

A)

Wrong

B)

Right

C)

Can not say

D)

None of the above

Correct Answer : Right

178 .

The Whitworth quick return motion mechanism is formed in a slider crank chain when the

A)

slider is a fixed link

B)

longest link is a fixed link

C)

coupler link is fixed

D)

smallest link is a fixed link

Correct Answer : coupler link is fixed

179 .

The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is

A)

0Â° and 90Â°

B)

0Â° and 180Â°

C)

90Â° and 180Â°

D)

180Â° and 360Â°

Correct Answer : 0Â° and 180Â°

180 .

If Ï‰/Ï‰n is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach

A)

0Â°

B)

90Â°

C)

180Â°

D)

360Â°

Correct Answer : 180Â°

181 .

What is the working depth of the gear and the pinion of the bevel gears?

A)

2 m, 0.7 m

B)

3 m, 0.4 m

C)

0.7 m, 2 m

D)

0.4 m, 3 m

Correct Answer : 2 m, 0.7 m

Explanation : The working depth of the teeth is usually 2 m which is the same as for standard spur and helical gears, but the bevel pinion is designed with the larger addendum and has 0.7 m working depth. The gear addendum varies according to the gear ratio and is 1 m for a gear ratio of 1.

182 .

In a centrifugal clutch, what is Ï‰?

A)

Angular acceleration of the pulley

B)

Angular running speed at which the engagement takes place

C)

Angular running speed of the pulley

D)

Angular acceleration at which the engagement begins to take place

Correct Answer : Angular running speed of the pulley

Explanation : In a centrifugal clutch, ω is the angular running speed of the body. ω1 is the angular speed at which the engagement begins to take place.

183 .

When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be

A)

stable

B)

unstable

C)

isochronous

D)

None of the above

Correct Answer : unstable

184 .

The factor which affects the critical speed of a shaft is

A)

eccentricity

B)

span of shaft

C)

diameter of disc

D)

All of the above

Correct Answer : All of the above

185 .

The partial balancing of reciprocating parts in locomotives produces

A)

hammer blow

B)

swaying couple

C)

variation in tractive force along the line of stroke

D)

All of the above

Correct Answer : All of the above

186 .

The inversion of a mechanism is

A)

turning its upside down

B)

changing of a higher pair to a lower pair

C)

obtained by fixing different links in a kinematic chain

D)

obtained by reversing the input and output motion

Correct Answer : obtained by fixing different links in a kinematic chain

187 .

When the nature of contact between the elements of a pair is such that it can only slide relative to the other, the pair is known as a

A)

sliding pair

B)

screw pair

C)

turning pair

D)

spherical pair

Correct Answer : sliding pair

188 .

If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be

A)

stable

B)

unstable

C)

isochronous

D)

None of the above

Correct Answer : isochronous

189 .

If the controlling force line for a spring controlled governor when produced intersects the Y-axis above the origin, then the governor is said to be unstable.

A)

Right

B)

Wrong

C)

Can not say

D)

None of the above

Correct Answer : Right

190 .

The product of the diametral pitch and module is equal to one.

A)

Correct

B)

Incorrect

C)

Can not say

D)

None of the above

Correct Answer : Correct

191 .

Which of the following is a higher pair?

A)

Screw pair

B)

Belt and pulley

C)

Sliding pair

D)

Turning pair

Correct Answer : Belt and pulley

192 .

When the belt is stationary, it is subjected to some tension known as initial tension. The value of this tension is equal to the

A)

tension in the tight side of the belt

B)

tension in the slack side of the belt

C)

average tension of the tight side and slack side of the belt

D)

sum of the tensions on the tight side and slack side of the belt

Correct Answer : average tension of the tight side and slack side of the belt

193 .

In a force-closed pair, the two elements of a pair are not held together mechanically.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Disagree

194 .

The coriolis component of acceleration acts

A)

along the sliding surface

B)

at 45Â° to the sliding surface

C)

parallel to the sliding surface

D)

perpendicular to the sliding surface

Correct Answer : perpendicular to the sliding surface

195 .

When a body moves with simple harmonic motion, the product of its periodic time and frequency is equal to

A)

one

B)

Ï€

C)

Ï€/2

D)

zero

Correct Answer : one

196 .

In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to

A)

0.2

B)

0.4

C)

0.6

D)

0.8

Correct Answer : 0.6

197 .

For high speed engines, the cam follower should move with

A)

cycloidal motion

B)

uniform velocity

C)

simple harmonic motion

D)

uniform acceleration and retardation

Correct Answer : cycloidal motion

198 .

In a coupling rod of a locomotive, each of the four pairs is a __________ pair.

A)

screw

B)

turning

C)

sliding

D)

rolling

Correct Answer : turning

199 .

The height of a Watt's governor is

A)

directly proportional to speed

B)

inversely proportional to speed

C)

directly proportional to (speed)Â²

D)

inversely proportional to (speed)Â²

Correct Answer : inversely proportional to (speed)Â²

200 .

A rotor supported at A and B carries two masses as shown in the below figure. The rotor is

A)

statically balanced

B)

dynamically balanced

C)

statically and dynamically balanced

D)

Not balanced

Correct Answer : statically and dynamically balanced

201 .

Which of the following statement is correct?

A)

The velocity of a particle moving with simple harmonic motion is zero at the mean position.

B)

The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.

C)

The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.

D)

The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.

Correct Answer : The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.

202 .

When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be

A)

hunt

B)

stable

C)

unstable

D)

isochronous

Correct Answer : hunt

203 .

The maximum frictional force, which comes into play, when an body just begins to slide over the surface of the other body, is known as

A)

static friction

B)

limiting friction

C)

dynamic friction

D)

coefficient of friction

Correct Answer : limiting friction

204 .

In a four stroke I.C. engine, the turning moment during the compression stroke is

A)

positive throughout

B)

negative throughout

C)

positive during major portion of the stroke

D)

negative during major portion of the stroke

Correct Answer : negative throughout

205 .

The displacement of the D-slide valve is __________ the steam lap by a distance known as lead of the valve.

A)

greater than

B)

less than

C)

Can not say

D)

None of the above

Correct Answer : greater than

206 .

In the two rotor system as shown in the below figure (I1 < I2), a node of vibration is situated

A)

nearer to I1 but outside

B)

between I1, and I2 but nearer I1

C)

between I1, and I2 but nearer to I2

D)

exactly in the middle of the shaft

Correct Answer : between I1, and I2 but nearer to I2

207 .

For static balancing of a shaft, the net dynamic force acting on the shaft is equal to zero.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Agree

208 .

A spring controlled governor is said to be unstable, if the relation between the controlling force (Fc) and radius of rotation (r) is Fc = ar.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Disagree

209 .

The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a left turn. The effect of gyroscopic couple acting on it will be

A)

to lower the bow and stern

B)

to raise the bow and stern

C)

to raise the bow and lower the stern

D)

to raise the stern and lower the bow

Correct Answer : to raise the bow and lower the stern

210 .

When a slider moves on a fixed link having curved surface, their instantaneous centre lies

A)

at the pin joint

B)

at the centre of circle

C)

on their point of contact

D)

at the centre of curvature

Correct Answer : at the centre of curvature

211 .

The frictional torque transmitted in a conical pivot bearing with assumption of uniform pressure is __________ as compared to uniform wear.

A)

less

B)

more

C)

same

D)

None of the above

Correct Answer : more

212 .

Scotch yoke mechanism is used to generate

A)

logarithms

B)

inversions

C)

square roots

D)

sine functions

Correct Answer : sine functions

213 .

The balancing of a rigid rotor can be achieved by appropriately placing balancing masses in

A)

a single plane

B)

two planes

C)

three planes

D)

four planes

Correct Answer : two planes

214 .

The unbalanced primary forces in a reciprocating engine are

A)

balanced partially

B)

not balanced

C)

balanced completely

D)

balanced by secondary forces

Correct Answer : balanced partially

215 .

The swaying couple is due to the

A)

partial balancing

B)

secondary unbalanced force

C)

primary unbalanced force

D)

two cylinders of locomotive

Correct Answer : primary unbalanced force

216 .

The lead screw of a lathe with nut forms a

A)

rolling pair

B)

screw pair

C)

turning pair

D)

sliding pair

Correct Answer : screw pair

217 .

The angle of the inclined plane at which the body just begins to slide down the plane, is called helix angle.

A)

Right

B)

Wrong

C)

Can not say

D)

None of the above

Correct Answer : Wrong

218 .

The danger of breakage and vibration is maximum

A)

near the critical speed

B)

below the critical speed

C)

above the critical speed

D)

None of the above

Correct Answer : near the critical speed

219 .

For two governors A and B, the lift of sleeve of governor A is more than that of governor B, for a given fractional change in speed. It indicates that

A)

governor A is more sensitive than governor B

B)

governor B is more sensitive than governor A

C)

both governors A and B are equally sensitive

D)

None of the above

Correct Answer : governor A is more sensitive than governor B

220 .

In a multiple V-belt drive, if one of the belt is broken, then we should replace

A)

all the belts

B)

the broken belt only

C)

the broken belt and the belts on either side of it

D)

None of the above

Correct Answer : all the belts

221 .

The component of the acceleration, parallel to the velocity of the particle, at the given instant is called

A)

radial component

B)

coriolis component

C)

tangential component

D)

None of the above

Correct Answer : tangential component

222 .

A reed type tachometer use the principle of

A)

torsional vibration

B)

transverse vibration

C)

damped free vibration

D)

longitudinal vibration

Correct Answer : transverse vibration

223 .

When the sleeve of a Porter governor moves upwards, the governor speed

A)

increases

B)

decreases

C)

remains unaffected

D)

first increases and then decreases

Correct Answer : increases

224 .

A thin circular disc is rolling with a uniform linear speed, along a straight path on a plane surface. Which of the following statement is correct in this regard?

A)

All points of the disc have the same velocity

B)

The centre of the disc has zero acceleration

C)

The centre of the disc has centrifugal acceleration

D)

The point on the disc making contact with the plane surface has zero acceleration

Correct Answer : The centre of the disc has zero acceleration

225 .

The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by (where OQ = Distance between the centre of circular flank and centre of nose)

A)

ω² x OQ

B)

ω² x OQ sin θ

C)

ω² x OQ cos θ

D)

ω² x OQ tan θ

Correct Answer : ω² x OQ

226 .

For an involute gear, the ratio of base circle radius and pitch circle radius is equal to

A)

sin Ï†

B)

cos Ï†

C)

sec Ï†

D)

cosec Ï†

Correct Answer : cos Ï†

227 .

Which of the following is an open pair?

A)

Journal bearing

B)

Lead screw and nut

C)

Cam and follower

D)

Ball and socket joint

Correct Answer : Cam and follower

228 .

The frictional torque transmitted in a flat pivot bearing with assumption of uniform pressure is __________ as compared to uniform wear.

A)

more

B)

less

C)

same

D)

None of the above

Correct Answer : more

229 .

The working depth of a gear is the radial distance from the

A)

pitch circle to the top of a tooth

B)

pitch circle to the bottom of a tooth

C)

top of a tooth to the bottom of a tooth

D)

addendum circle to the clearance circle

Correct Answer : addendum circle to the clearance circle

230 .

The cam and follower is an example of

A)

higher pair

B)

lower pair

C)

rolling pair

D)

sliding pair

Correct Answer : higher pair

231 .

When the axes of the first and last wheels are co-axial, then the train is known as

A)

reverted gear train

B)

epicyclic gear train

C)

simple train of wheels

D)

compound train of wheels

Correct Answer : reverted gear train

232 .

The acceleration of a particle at any instant has two components i.e. radial component and tangential component. These two components will be

A)

inclined at 45Â°

B)

parallel to each other

C)

opposite to each other

D)

perpendicular to each other

Correct Answer : perpendicular to each other

233 .

The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where lâ‚ and lâ‚‚ = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)

A)

lâ‚ = kG

B)

lâ‚‚ = kG

C)

lâ‚lâ‚‚ = kG

D)

lâ‚lâ‚‚ = kG²

Correct Answer : lâ‚lâ‚‚ = kG²

234 .

A Porter governor is a

A)

inertia governor

B)

dead weight governor

C)

pendulum type governor

D)

spring loaded governor

Correct Answer : dead weight governor

235 .

The controlling force diagram for a spring controlled governor is a curve passing through the origin.

A)

Yes

B)

No

C)

Can not say

D)

None of the above

Correct Answer : No

236 .

The lower pairs are __________ pairs.

A)

self-closed

B)

force-closed

C)

Can not say

D)

None of the above

Correct Answer : self-closed

237 .

The arrangement is called bevel gearing, when two __________ are connected by gears.

A)

parallel and coplaner shafts

B)

parallel and non-coplaner shafts

C)

intersecting and coplaner shafts

D)

non-intersecting and non-coplaner shafts

Correct Answer : intersecting and coplaner shafts

238 .

The maximum fluctuation of speed is the

A)

sum of maximum and minimum speeds

B)

difference of the maximum and minimum speeds

C)

difference of minimum fluctuation of speed and the mean speed

D)

variations of speed above and below the mean resisting torque line

Correct Answer : difference of the maximum and minimum speeds

239 .

The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the

A)

unbalanced couples are caused only at higher speeds

B)

unbalanced forces are not dangerous at higher speeds

C)

effects of unbalances are directly proportional to the speed

D)

effects of unbalances are proportional to the square of the speed

Correct Answer : effects of unbalances are proportional to the square of the speed

240 .

When the sleeve of a Porter governor moves downwards, the governor speed

A)

increases

B)

decreases

C)

remains unaffected

D)

first increases and then decreases

Correct Answer : decreases

241 .

In a steam engine, the distance by which the outer edge of the D-slide valve overlaps the steam port is called

A)

steam lap

B)

lead

C)

exhaust lap

D)

None of the above

Correct Answer : steam lap

242 .

When brakes are applied to all the four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be

A)

zero

B)

minimum

C)

maximum

D)

None of the above

Correct Answer : minimum

243 .

When one of the links of a kinematic chain is fixed, the chain is known as a

A)

machine

B)

structure

C)

mechanism

D)

inversion

Correct Answer : mechanism

244 .

The displacement of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by (where R = Radius of flank, râ‚ = Minimum radius of the cam, and θ = Angle turned through by the cam)

A)

R(1 - sin θ)

B)

R(1 - cos θ)

C)

(R - râ‚)(1 - cos θ)

D)

(R - râ‚)(1 - sin θ)

Correct Answer : (R - râ‚)(1 - cos θ)

245 .

The contact ratio is the ratio of

A)

length of arc of recess to the circular pitch

B)

length of arc of approach to the circular pitch

C)

length of arc of contact to the circular pitch

D)

length of pair of contact to the circular pitch

Correct Answer : length of arc of contact to the circular pitch

246 .

An exact straight line motion mechanism is a

A)

Hart's mechanism

B)

Peaucellier's mechanism

C)

Scott-Russell's mechanism

D)

All of the above

Correct Answer : All of the above

247 .

A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)

A)

P = W (sin α + μ cos α)

B)

P = W (cos α + μ sin α)

C)

P = W tan α

D)

P = W tan (α + φ)

Correct Answer : P = W (sin α + μ cos α)

248 .

When a shaking force is transmitted through the springs, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than

A)

0.25

B)

0.5

C)

1

D)

âˆš2

Correct Answer : âˆš2

249 .

Which of the following is a spring controlled governor?

A)

Hartung governor

B)

Hartnell governor

C)

Wilson-Hartnell governor

D)

All of the above

Correct Answer : All of the above

250 .

At the nodal point in a shaft, the amplitude for torsional vibration will be

A)

zero

B)

minimum

C)

maximum

D)

infinity

Correct Answer : zero

251 .

When a body is subjected to transverse vibrations, the stress induced in a body will be

A)

shear stress

B)

bending stress

C)

tensile stress

D)

compressive, stress

Correct Answer : bending stress

252 .

Which of the following statement is correct for gears?

A)

The addendum is less than the dedendum

B)

The contact ratio means the number of pairs of teeth in contact

C)

The pitch circle diameter is the product of module and number of teeth

D)

All of the above

Correct Answer : All of the above

253 .

The minimum number of teeth on the pinion which will mesh with any gear without interference for 20Â° full depth involute teeth will be

A)

12

B)

14

C)

18

D)

24

Correct Answer : 18

254 .

In a screw jack, the effort required to lift the load W is given by (where Î± = Helix angle, and Ï† = Angle of friction)

A)

P = W tan(Î± - Ï†)

B)

P = W tan(Ï† - Î±)

C)

P = W tan(Î± + Ï†)

D)

P = W cos(Î± + Ï†)

Correct Answer : P = W tan(Î± + Ï†)

255 .

The coriolis component of acceleration leads the sliding velocity by

A)

45Â°

B)

90Â°

C)

135Â°

D)

180Â°

Correct Answer : 90Â°

256 .

In order to facilitate starting of locomotive in any position, the cranks of a locomotive with two cylinders, are placed at

A)

45Â° to each other

B)

90Â° to each other

C)

120Â° to each other

D)

180Â° to each other

Correct Answer : 90Â° to each other

257 .

In a mechanism, the fixed instantaneous centres are those centres which

A)

vary with the configuration of the mechanism

B)

moves as the mechanism moves, but joints are of permanent nature

C)

remain in the same place for all configurations of the mechanism

D)

None of the above

Correct Answer : remain in the same place for all configurations of the mechanism

258 .

A link or element need not to be a rigid body, but it must be a resistant body.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Agree

259 .

A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a

A)

mechanism

B)

inversion

C)

structure

D)

kinematic chain

Correct Answer : kinematic chain

260 .

Which of the following statements regarding laws governing the friction between dry surfaces are correct?

A)

The friction force is independent of me area of contact.

B)

The friction force is directly proportional to the normal force.

C)

The friction force is dependent on the materials of the contact surfaces.

D)

All of the above

Correct Answer : All of the above

261 .

In a multi plate clutch, T = 150 N-m, n = 4, Âµ = 0.3 and R = 0.1 m. Find the axial thrust.

A)

18

B)

200

C)

1250

D)

1800

Correct Answer : 1250

Explanation : T = nµWR
150 = 4 x 0.3 x W x 0.1
W = 1250 N
Thus, the axial thrust = 1250 N.

262 .

Which of the following clutches include shoes and spider inside the rim of the pulley?

A)

Cone clutch

B)

Centrifugal clutch

C)

Multi plate clutch

D)

Single plate clutch

Correct Answer : Centrifugal clutch

Explanation : Centrifugal clutches are incorporated into motor pulleys which consist of a number of shoes on inside of the rim of the pulley. These clutches are generally incorporated into the motor pulleys. The outer surfaces of the shoe are covered with a layer of a friction material.

263 .

Creep in belt drive is due to

A)

expansion of the belt

B)

weak material of the belt

C)

weak material of the pulley

D)

uneven extensions and contractions of the belt when it passes from tight side to slack side

Correct Answer : uneven extensions and contractions of the belt when it passes from tight side to slack side

264 .

A watt's governor can work satisfactorily at speeds from

A)

60 to 80 r.p.m.

B)

80 to 100 r.p.m.

C)

100 to 200 r.p.m.

D)

200 to 300 r.p.m.

Correct Answer : 60 to 80 r.p.m.

265 .

The size of a gear is usually specified by

A)

circular pitch

B)

pressure angle

C)

diametral pitch

D)

pitch circle diameter

Correct Answer : pitch circle diameter

266 .

Which one of the following can completely balance several masses revolving in different planes on a shaft?

A)

Two equal masses in any two planes

B)

Two masses in any two planes

C)

A single mass in different planes

D)

A single mass in one of the planes of the revolving masses

Correct Answer : Two masses in any two planes

267 .

The angle which the normal reaction makes with the resultant reaction is called angle of friction.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Agree

268 .

The example of successfully constrained motion is a

A)

motion of an I.C. engine valve

B)

piston reciprocating inside an engine cylinder

C)

motion of the shaft between a foot-step bearing

D)

All of the above

Correct Answer : All of the above

269 .

A system in dynamic balance implies that

A)

the system is critically damped

B)

there is no critical speed in the system

C)

the system is also statically balanced

D)

there will absolutely no wear of bearings

Correct Answer : the system is also statically balanced

270 .

The example of completely constrained motion is a

A)

motion of a square bar in a square hole

B)

motion of a piston in the cylinder of a steam engine

C)

motion of a shaft with collars at each end in a circular hole

D)

All of the above

Correct Answer : All of the above

271 .

In involute gears, the pressure angle is

A)

always constant

B)

always variable

C)

dependent on the size of teeth

D)

dependent on the size of gears

Correct Answer : always constant

272 .

The cam follower generally used in air-craft engines is

A)

flat faced follower

B)

roller follower

C)

knife edge follower

D)

spherical faced follower

Correct Answer : roller follower

273 .

The factional torque for square thread at the mean radius r while raising load W is given by

A)

T = W.r tan Î±

B)

T = W.r tan Ï†

C)

T = W.r tan(Ï† - Î±)

D)

T = W.r tan(Ï† + Î±)

Correct Answer : T = W.r tan(Ï† + Î±)

274 .

If Ï‰/Ï‰n is very low for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach

A)

0Â°

B)

90Â°

C)

180Â°

D)

360Â°

Correct Answer : 0Â°

275 .

In a locomotive, the maximum magnitude of the unbalanced force along the perpendicular to the line of stroke, is known as

A)

swaying couple

B)

tractive force

C)

hammer blow

D)

None of the above

Correct Answer : hammer blow

276 .

For low and moderate speed engines, the cam follower should move with

A)

uniform velocity

B)

cycloidal motion

C)

simple harmonic motion

D)

uniform acceleration and retardation

Correct Answer : simple harmonic motion

277 .

A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal force

A)

the reaction on the front wheels increases and on the rear wheels decreases

B)

the reaction on the outer wheels increases and on the inner wheels decreases

C)

the reaction on the rear wheels increases and on the front wheels decreases

D)

the reaction on me inner wheels increases and on the outer wheels decreases

Correct Answer : the reaction on the outer wheels increases and on the inner wheels decreases

278 .

In order to give a complete secondary balance of a multi-cylinder in-line engine,

A)

the algebraic sum of the secondary forces must be equal to zero

B)

the algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

279 .

A point B on a rigid link AB moves with respect to A with angular velocity Ï‰ rad/s. The total acceleration of B with respect to A will be equal to

A)

vector sum of radial component and coriolis component

B)

vector sum of radial component and tangential component

C)

vector sum of tangential component and coriolis component

D)

vector difference of radial component and tangential component

Correct Answer : vector sum of radial component and tangential component

280 .

A spring controlled governor is said to be stable if the controlling force line when produced intersects the Y-axis

A)

below the origin

B)

at the origin

C)

above the origin

D)

All of the above

Correct Answer : below the origin

281 .

When the radius of rotation of balls __________ as the equilibrium speed increases, the governor is said to be unstable.

A)

increases

B)

decreases

C)

remains constant

D)

None of the above

Correct Answer : decreases

282 .

The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

A)

to dip the nose and tail

B)

to raise the nose and tail

C)

to dip the nose and raise the tail

D)

to raise the nose and dip the tail

Correct Answer : to raise the nose and dip the tail

283 .

In a simple harmonic motion, the velocity vector with respect to displacement vector

A)

leads by 90Â°

B)

leads by 180Â°

C)

lags by 90Â°

D)

is in phase

Correct Answer : lags by 90Â°

284 .

When a point moves along a straight line, its acceleration will have

A)

radial component only

B)

coriolis component only

C)

radial and tangential components both

D)

tangential component only

Correct Answer : tangential component only

285 .

A mechanism is an assemblage of

A)

two links

B)

three links

C)

four or more than four links

D)

None of the above

Correct Answer : four or more than four links

286 .

Which of the following is used to control the speed variations of the engine caused by the fluctuations of the engine turning moment?

A)

Flywheel

B)

Governor

C)

D-slide valve

D)

Meyer's expansion valve

Correct Answer : Flywheel

287 .

A Hartnell governor is a

A)

inertia governor

B)

spring loaded governor

C)

dead weight governor

D)

pendulum type governor

Correct Answer : spring loaded governor

288 .

The relation between number of pairs (p) forming a kinematic chain and the number of links (l) is

A)

l = 2p - 5

B)

l = 2p - 4

C)

l = 2p - 3

D)

l = 2p - 2

Correct Answer : l = 2p - 4

289 .

Frequency of vibrations is usually expressed in

A)

number of cycles per hour

B)

number of cycles per minute

C)

number of cycles per second

D)

None of the above

Correct Answer : number of cycles per second

290 .

The ratio of driving tensions for rope drive is same as that of V-belt drive.

A)

Yes

B)

No

C)

Can not say

D)

None of the above

Correct Answer : Yes

291 .

In a steam engine, the link constitutes a

A)

crank pin, crankshaft and flywheel

B)

piston, piston rod and crosshead

C)

connecting rod with big and small end brasses, caps and bolts

D)

All of the above

Correct Answer : All of the above

292 .

The secondary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is

A)

0Â° and 90Â°

B)

180Â° and 360Â°

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

293 .

For dynamic balancing of a shaft

A)

the net dynamic force acting on the shaft is equal to zero

B)

the net couple due to the dynamic forces acting on the shaft is equal to zero

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

294 .

In a kinematic chain, a quaternary joint is equivalent to

A)

four binary joints

B)

three binary joints

C)

two binary joints

D)

one binary joint

Correct Answer : three binary joints

295 .

The load cup of a screw jack is made separate from the head of the spindle to

A)

prevent the rotation of load being lifted

B)

enhance the load carrying capacity of the jack

C)

reduce the effort needed for lifting the working load

D)

reduce the value of frictional torque required to be countered for lifting the load

Correct Answer : prevent the rotation of load being lifted

296 .

In an open pair, the two elements of a pair

A)

are not held together mechanically

B)

have a surface contact when in motion

C)

have a line or point contact when in motion

D)

are kept in contact by the action of external forces, when in motion

Correct Answer : are not held together mechanically

297 .

The ratio of the driving tensions for V-belts is __________ times that of flat belts. (where Î² = Semi-angle of the groove)

A)

sin Î²

B)

cos Î²

C)

sec Î²

D)

cosec Î²

Correct Answer : cosec Î²

298 .

The secondary unbalanced force is __________ the primary unbalanced force.

A)

n times

B)

1/n times

C)

one-half

D)

two-third

Correct Answer : 1/n times

299 .

The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because

A)

whole of the mechanism in the Ackerman steering gear is on the back of the front wheels

B)

the Ackerman steering gear consists of turning pairs

C)

Both (A) and (B)

D)

the Ackerman steering gear is most economical

Correct Answer : Both (A) and (B)

300 .

The instantaneous centre of a rigid thin disc rolling on a plane rigid surface is located at

A)

the centre of the disc

B)

the point of contact

C)

an infinite distance on the plane surface

D)

the point on the circumference situated vertically opposite to the contact point

Correct Answer : the point of contact

301 .

The coefficient of fluctuation of speed is __________ of maximum fluctuation of speed and the mean speed.

A)

ratio

B)

sum

C)

product

D)

difference

Correct Answer : ratio

302 .

A rigid body, under the action of external forces, can be replaced by two masses placed at a fixed distance apart. The two masses form an equivalent dynamical system, if

A)

the sum of the two masses is equal to the total mass of body

B)

the centre of gravity of the two masses coincides with that of the body

C)

the sum of mass moment of inertia of the masses about their centre of gravity is equal to the mass moment of inertia of the body

D)

All of the above

Correct Answer : All of the above

303 .

When two pulleys are connected by means of a cross belt drive, then both the pulleys will rotate in __________ directions.

A)

same

B)

opposite

C)

Both (A) and (B)

D)

Can not Say

Correct Answer : opposite

304 .

The total number of instantaneous centres for a mechanism consisting of n links are

A)

n

B)

n/2

C)

n - 1

D)

n(n - 1)/2

Correct Answer : n(n - 1)/2

305 .

The coriolis component of acceleration depends upon

A)

velocity of slider

B)

angular velocity of the link

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Both (A) and (B)

306 .

A mechanism __________ for transmitting or transforming motion.

A)

can be used

B)

can not be used

C)

Both (A) and (B)

D)

None of the above

Correct Answer : can be used

307 .

The distance moved by the valve from one end to the other end is called valve travel.

A)

True

B)

False

C)

Can not say

D)

None of the above

Correct Answer : True

308 .

The Klein's method of construction for reciprocating engine mechanism

A)

is based on the acceleration diagram

B)

enables determination of coriolis component

C)

is a simplified version of instantaneous centre method

D)

utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine

Correct Answer : utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine

309 .

The velocity of the rubbing surface __________ with the distance from the axis of the bearing.

A)

increases

B)

decreases

C)

Can not say

D)

None of the above

Correct Answer : increases

310 .

In Meyer's expansion valve, the main valve is driven by an eccentric having an angle of advance from

A)

10Â° - 15Â°

B)

15Â° - 25Â°

C)

25Â° - 30Â°

D)

30Â° - 40Â°

Correct Answer : 25Â° - 30Â°

311 .

There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is

A)

1/24

B)

1/8

C)

4/15

D)

12

Correct Answer : 1/24

312 .

A kinematic chain is known as a mechanism when

A)

none of the links is fixed

B)

one of the links is fixed

C)

two of the links are fixed

D)

None of the above

Correct Answer : one of the links is fixed

313 .

The Klein's diagram is used when

A)

crank has uniform angular velocity

B)

crank has uniform angular accleration

C)

crank has non-uniform angular velocity

D)

crank has non-uniform angular acceleration

Correct Answer : crank has uniform angular velocity

314 .

An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called

A)

dedendum circle

B)

addendum circle

C)

clearance circle

D)

pitch circle

Correct Answer : pitch circle

315 .

The natural frequency of free transverse vibrations is same as that of free longitudinal vibrations.

A)

Right

B)

Wrong

C)

Can not say

D)

None of the above

Correct Answer : Right

316 .

The height of a Watt's governor (in metres) is equal to (where N = Speed of the arm and ball about the spindle axis)

A)

8.95/NÂ²

B)

89.5/NÂ²

C)

895/NÂ²

D)

8950/NÂ²

Correct Answer : 895/NÂ²

317 .

V-belts are usually used for

A)

long drives

B)

short drives

C)

long and short drives

D)

None of the above

Correct Answer : short drives

318 .

In a pantograph, all the pairs are

A)

sliding pairs

B)

turning pairs

C)

spherical pairs

D)

self-closed pairs

Correct Answer : turning pairs

319 .

The relative velocity of B with respect to A in a rigid link AB is

A)

along AB

B)

at 45Â° to AB

C)

parallel to AB

D)

perpendicular to AB

Correct Answer : perpendicular to AB

320 .

Sensitiveness of the governor is defined as the ratio of the

A)

mean speed to the minimum equilibrium speed

B)

mean speed to the maximum equilibrium speed

C)

sum of the maximum and minimum equilibrium speeds to the mean speed

D)

difference of the maximum and minimum equilibrium speeds to the mean speed

Correct Answer : difference of the maximum and minimum equilibrium speeds to the mean speed

321 .

The two parallel and coplaner shafts are connected by gears having teeth parallel to the axis of the shaft. This arrangement is known as

A)

spur gearing

B)

bevel gearing

C)

spiral gearing

D)

helical gearing

Correct Answer : spur gearing

322 .

When the particles of a body moves perpendicular to its axis, then the body is said to have

A)

torsional vibration

B)

transverse vibration

C)

longitudinal vibration

D)

None of the above

Correct Answer : transverse vibration

323 .

The power from the engine to the rear axle of an automobile is transmitted by means of

A)

spur gears

B)

bevel gears

C)

Hooke's joint

D)

worm and worm wheel

Correct Answer : Hooke's joint

324 .

A slider moves at a velocity v on a link revolving at Ï‰ rad/s. The coriolis component of acceleration is

A)

Ï‰v

B)

2 Ï‰v

C)

Ï‰Â²v

D)

2 Ï‰vÂ²

Correct Answer : 2 Ï‰v

325 .

In a reciprocating steam engine, which of the following forms a kinematic link?

A)

Crankshaft and flywheel

B)

Cylinder and piston

C)

Flywheel and engine frame

D)

Piston rod and connecting rod

Correct Answer : Crankshaft and flywheel

326 .

Under logarithmic decrement, the amplitude of successive vibrations are

A)

constant

B)

in arithmetic progression

C)

in logarithmic progression

D)

in geometric progression

Correct Answer : in geometric progression

327 .

The efficiency of a screw jack is maximum, when (where Î± = Helix angle, and Ï† = Angle of friction)

A)

Î± = 45Â° -

B)

Î± = 45Â° +

C)

Î± = 90Â° - Ï†

D)

Î± = 90Â° + Ï†

Correct Answer : Î± = 45Â° -

328 .

In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is Constant, then

A)

open belt drive is recommended

B)

crossed belt drive is recommended

C)

both open belt drive and crossed belt drive is recommended

D)

the drive is recommended depending upon the torque transmitted

Correct Answer : crossed belt drive is recommended

329 .

A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is

A)

2

B)

3

C)

4

D)

5

Correct Answer : 5

330 .

Which of the following is an example of a higher pair?

A)

Toothed gearing

B)

Belt and rope drive

C)

Ball and roller bearing

D)

All of the above

Correct Answer : All of the above

331 .

The velocity of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by

A)

Ï‰râ‚ sin Î¸

B)

Ï‰R cos Î¸

C)

Ï‰(R - râ‚)sin Î¸

D)

Ï‰(R - râ‚)cos Î¸

Correct Answer : Ï‰(R - râ‚)sin Î¸

332 .

Which of the following property of the instantaneous centre is correct?

A)

The two rigid links have no linear velocity relative to each other at the instantaneous centre.

B)

A rigid link rotates instantaneously relative to another link at the instantaneous centre for the configuration of the mechanism considered.

C)

The velocity of the instantaneous centre relative to any third rigid link is same whether the instantaneous centre is regarded as a point on the first rigid link or on the second rigid link.

D)

All of the above

Correct Answer : All of the above

333 .

In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to

A)

ensure uniform loading

B)

reduce slip

C)

reduce vibration

D)

ensure proper alignment

Correct Answer : ensure uniform loading

334 .

A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is

A)

5367 r.p.m.

B)

6000 r.p.m.

C)

9360 r.p.m.

D)

12000 r.p.m

Correct Answer : 5367 r.p.m.

335 .

Torsional vibrations are said to occur when the particles of a body moves

A)

parallel to its axis

B)

in a circle about its axis

C)

perpendicular to its axis

D)

None of the above

Correct Answer : in a circle about its axis

336 .

For the isochronous Porter governor, the controlling force curve is a straight line passing through the origin.

A)

Correct

B)

Incorrect

C)

Can not say

D)

None of the above

Correct Answer : Correct

337 .

The uniform pressure theory gives a higher frictional torque than the uniform wear theory.

A)

Agree

B)

Disagree

C)

Can not say

D)

None of the above

Correct Answer : Agree

338 .

The train value of a gear train is

A)

always less than unity

B)

always greater than unity

C)

equal to velocity ratio of a gear train

D)

reciprocal of velocity ratio of a gear train

Correct Answer : reciprocal of velocity ratio of a gear train

339 .

The product of the diametral pitch and circular pitch is equal to

A)

1

B)

1/Ï€

C)

Ï€

D)

2 Ï€

Correct Answer : Ï€

340 .

The coriolis component of acceleration is taken into account for

A)

slider crank mechanism

B)

four bar chain mechanism

C)

quick return motion mechanism

D)

All of the above

Correct Answer : quick return motion mechanism

341 .

In gears, interference takes place when

A)

gear teeth are undercut

B)

pitch of the gears is not same

C)

gears do not move smoothly in the absence of lubrication

D)

the tip of a tooth of a mating gear digs into the portion between base and root circles

Correct Answer : the tip of a tooth of a mating gear digs into the portion between base and root circles

342 .

Which of the following statement is correct for involute gears?

A)

The interference is inherently absent.

B)

The pressure angle is constant throughout the teeth engagement.

C)

A convex flank is always in contact with concave flank.

D)

The variation in centre distance of shafts increases radial force.

Correct Answer : The pressure angle is constant throughout the teeth engagement.

343 .

The ratio of maximum fluctuation of speed to the mean speed is called

A)

fluctuation of speed

B)

maximum fluctuation of speed

C)

coefficient of fluctuation of speed

D)

None of the above

Correct Answer : coefficient of fluctuation of speed

344 .

The brake commonly used in railway trains is

A)

shoe brake

B)

band brake

C)

band and block brake

D)

internal expanding brake

Correct Answer : shoe brake

345 .

The acceleration of the particle moving with simple harmonic motion is __________ at the mean position.

A)

zero

B)

minimum

C)

maximum

D)

None of the above

Correct Answer : zero

346 .

The face of the tooth is the

A)

surface of the top of tooth

B)

width of tooth below the pitch surface

C)

width of tooth measured along the pitch circle

D)

surface of tooth above the pitch surface

Correct Answer : surface of tooth above the pitch surface

347 .

A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when

A)

a = 0 and b is + ve

B)

a is + ve and b = 0

C)

a is + ve and b is - ve

D)

a is + ve and b is also + ve

Correct Answer : a is + ve and b = 0

348 .

When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a

A)

governor

B)

flywheel

C)

D-slide valve

D)

Meyer's expansion valve

Correct Answer : governor

349 .

The D-slide valve is also known as

A)

piston slide valve

B)

outside admission valve

C)

inside admission valve

D)

None of the above

Correct Answer : outside admission valve

350 .

A rotor which is balanced statically but not dynamically is supported on two bearings L apart and at high speed of the rotor, reaction on the left bearing is R. The right side of the bearing is shifted to a new position 2 L apart from the left bearing. At the same rotor speed, dynamic reaction on the left bearing in the new arrangement will

A)

become equal to 2 R

B)

become equal to R/2

C)

become equal to R/4

D)

remain same as before

Correct Answer :