Question

A steel wire and a copper wire, each of diameter 2.000 mm, are joined end to end. At 48.0°C, each has an unstretched length of 2.000 m. The wires are connected between two fixed supports 4.000 m apart on a tabletop. The steel wire extends from x = −2.000 m to x = 0, the copper wire extends from x = 0 to x = 2.000 m, and the tension is negligible. The temperature is then lowered to 17.0°C. Assume the average coefficient of linear expansion of steel is 1.10x10^-5(°C)−1 and that of copper is 1.70x10^-5(°C)−1. Take Young's modulus for steel to be 2.00 1011 N/m2 and that for copper to be 1.10x10^11 N/m2.

(a) At this lower temperature, find the tension in the wire.

(b) At this lower temperature, find the x coordinate of the junction between the wires.

I got 465.6 for A and -0.233 for B and both were incorrect. Not sure what to do!