TYPE 3: PROBLEMS ON COMPARISON AND REPLACEMENT OF SHAFTS

Problem 1. A solid circular shaft of diameter 200mm has same cross section as that of hollow shaft of same material with inside diameter as 150mm. Find ratio of power transmitted by two shafts at same speed.

Problem 2 : Compare the weight of a solid shaft with that of hollow shaft to transmit given power at a given speed with a given maximum shear stress. The inside diameter of the hollow shaft is 2/3 of the outside diameter.

Problem 3.A solid circular shaft is replaced by a hollow circular shaft of the same material to transmit the same power. If the inside diameter of the hollow is 3/4 of outside diameter, find the saving in material, if any, by this replacement.

Problem 4 .A hollow shaft is of the same external diameter as that of the solid shaft. The inside diameter of the hollow shaft being half the external diameter. Both the shafts have the same material and length. Then show that the ratio of torque transmitted by hollow shaft to the torque transmitted by solid shaft is 0.9375.

Problem 5 : To transmit the same torque, a solid circular shaft 80 mm in diameter is to be replaced by a hollow circular shaft having external diameter 1.5 times the internal diameter. The material for solid and hollow shaft is the same. Determine the diameters of the hollow shaft.