Correct Answer : Option (A) : Hexagon
Explanation : In maximum shear stress theory we have the following equations: σ1= ±S(yt)σ2= ±S (yt), σ1 – σ2 =±S (yt) assuming S(yt)=S(yc).
Correct Answer : Drums with helical grooves
Explanation : They have more bearing surface of the drum and prevent friction between adjacent turns of the rope.
Correct Answer : Increasingly centrifugal force in large sheaves
Explanation : Larger sheaves have higher centrifugal forces and higher cost because more material is used in their construction.
Correct Answer : Both bending and tensile stress
Explanation : There is direct tensile stress due to load being raised as well as bending stress.