A composite shaft consists of copper rod of 30mm diameter enclosed in a steel tube of external diameter 50mm and 10 mm thick. The shaft is needed to transmit a shaft is required to transmit a torque of 1000N-m. Evaluate the shear stresses developed in copper and steel, if both the shaft has equal length and welded to a plate at each end, so that their twists are equal. Take modulus of rigidity for steel as twice that of copper.