A 2m long and 40 mm diameter aluminium shaft is to be replaced by a hollow steel shaft that will carry the same torque, of the same length and the same outside diameter with the same angle of twist over the total length. Determine the inside diameter of the hollow shaft. Take the modulus of rigidity of steel twice that of the aluminium. Assuming the modulus of rigidity of the steel shaft is 80 GPa, and the shaft transmits 5 kW at 150 rpm, find the: (a) (b) (c) The maximum shear stress The shear stress on the inside diameter The angle of twist per m length (33.6 mm, 47.2 MPa, 38.9 MPa, 1.69/m)n