Question

A steel beam is $5m$ long at a temperature of ${20}^{\circ }C$. On a hot day, the temperature rises to ${40}^{\circ }C$. What is the change in the length of the beam due to thermal expansion?

Coefficient of linear expansion of steel $\alpha =1.2\times {10}^{-5}{}^o{C}^{-1}$

Answer 1

We know that change in length $\Delta L=L\alpha \Delta T$

$\Delta T=40-20=20$ , L=5m

$\Delta L=5\times \alpha \times 20$

$\Delta L=5\times 1.2\times {10}^{-5}\times 20$

$=1.2\times {10}^{-3}$

$=1.2mm$