A shaft has to transmit a power of 6 kW at 200 rpm. Design (i) a solid circular shaft, and (ii) a hollow circular shaft with a 1.2 ratio of external to internal diameter. The maximum shear stress is...

A shaft has to transmit a power of 6 kW at 200 rpm. Design (i) a solid circular shaft, and (ii) a hollow circular shaft with a 1.2 ratio of external to internal diameter. The maximum shear stress is limited to 90 MPa and the angle of twist cannot be more than 3° per metre length. Find the weight ratio of the two shafts per metre length. G = 85 GPa.