Solutions

Both the copper bar and the steel tape expand due to the temperature change (1.3), as shown in the preceding figure. The exact final length of the copper bar lc for the initial length l0,c = 2000 mm and the temperature change \(\Delta \theta\) = 30 °C−(−10 °C) = 40 °C is where \(\alpha_{l,c} = 1.7 \times 10^{ - 5} \,\,{\text{K}}^{ - 1}\) is the linear expansion coefficient of copper.