A rod consisting of two cylindrical portions AB and BC is restrained at both ends. Portion AB is made of steel (E_s = 29 × 10? psi, ?_s = 6.5 × 10??/°F) and portion BC is made of aluminum (E_a = 10.4 × 10? psi, ?_a = 13.3 × 10??/°F). Knowing that the rod is initially unstressed, determine (a) the normal stresses induced in portions AB and BC by a temperature rise of 70°F, (b) the corresponding deflection of point B.