1. A solid steel shaft 4 m long is stressed to 70 MPa when twisted through 3°.
(a) Given that G = 83 GPa, find the diameter of the shaft.
(b) What power does this shaft transmit when running at 18 Hz?
2. Determine the maximum torque that can be applied to a hollow circular steel shaft of 100-mm outer diameter and 80-mm inner diameter. The shear stress is limited to 70 MPa, and the angle of twist must not exceed 0.4° in a length of 1.0 m. Use G = 83 GPa for steel.