712 *5-44 The propellers of a ship are connected to a solid A-36 steel shaft that is 60 m long and has an outer diame- ter of 340 mm and inner diameter of 260 mm. If the power output is 4.5 MW when the shaft rotates at 20 rad/s, deter- mine the maximum torsional stress in the shaft and its angle of twist. 5-45 A shaft is subjected to a torque T. Compare the effectiveness of using the tube shown in the figure with that of a solid section of radius c. To do this, compute the per- cent increase in torsional stress and angle of twist per unit length for the tube versus the solid section. T