Question: 1. Calculate the allowable torque that may be applied to a hollow circular shaft with an outside diameter of 150 mm and an inside diameter of 120 mm. The allowable shear stress is 75 MPa.
2. Design a hollow steel shaft to transmit a torque of 13,000 lb-in. The allowable shear stress in the shaft is 9000 psi. The outside diameter is to be twice the inside diameter.