The composite bar shown in Fig. P-273 is firmly attached to unyielding supports. An axial force P = 50 kips is applied at 60F. Compute the stress in each material at 120F. Assume a = 6.5 x 10-6 in/(in-F) for steel and 12.8 x 10-6 in/(in-F) for aluminum. Figure P-273 and P-274 Steel A = 3 in E = 29 x 106 psi Aluminum A = 2 in E = 10 x 106 psi 15 in 10 in