A hollow circular shaft, of outside diameter 50 mm and inside diameter 36 mm, is made of steel, for which the permissible stress in shear is 90 MPa and G = 85 GPa. Find the maximum torque that such a...

A hollow circular shaft, of outside diameter 50 mm and inside diameter 36 mm, is made of steel, for which the permissible stress in shear is 90 MPa and G = 85 GPa. Find the maximum torque that such a shaft can carry and the angle of twist per metre length.