The figure shows an inboard engine, 8-ft long steel drive shaft, and propeller for a motor boat. The shaft is to be designed to safely transmit 200 hp at 3500 rev/ min. Determine the diameter of the smallest shaft that can be used and its corresponding angle of twist. For the steel, use a working shear stress of 12 000 psi and G = 12 × 106 psi.
