Question:
Two steel rods and an aluminium rod of equal length $l_{0}$ and equal cross-section are joined rigidly at their ends as shown in figure below. All the rods are in the state of zero tension at $0^{\circ} \mathrm{C}$. Find the length of the system when the temperature is raised to $\theta$. Coefficient of linear expansion of aluminium and steel are $\alpha_{a}$ and $\alpha_{s}$ respectively. Young's modulus of aluminium is $Y_{a}$ and of steel is $Y_{s}$.
Solution:
