Two bars, one of steel and the other of copper having areas of cross-sections As and Ac, coefficient of expansion αs and αc and Young's Modulii Es and Es are rigidly connected together at the ends and subjected to temperature change of t°. If the lengt

Two bars, one of steel and the other of copper having areas of cross-sections A_s and A_c, coefficient of expansion αs and αc and Young's Modulii E_s and E_s are rigidly connected together at the ends and subjected to temperature change of t°. If the length of the bars initially is L, the final extension δ of the two bars at t° temperature is given by