A composite bar is made up of a brass rod of 25 mm diameter enclosed in a steel tube of 40 mm external diameter and 30 mm internal diameter as shown in Fig. 4.20. The rod and tube, being coaxial and equal in length, are securely fixed at each end. If the stresses in brass and steel are not to exceed 70 MPa and 120 MPa respectively, find the load (P) the composite bar can safely carry.Also find the change in length, if the composite bar is 500 mm long. Take E for steel tube as 200 GPa and brass rod as 80 GPa respectively.