# The length of a steel beam increases by 0.78 mm when its temperature is raised from 22 degrees C to 35 degrees C. What is the length of the beam at 22 degrees C (in meters)?

Jun 21, 2015

${l}_{0} = 4.545 m$
I may be wrong but I think you need something else...the expansion coefficient perhaps...?

#### Explanation:

You can use the expression that describes thermal linear expansion as:
$\Delta l = {l}_{0} \alpha \Delta T$
Where:
$\Delta l = l - {l}_{0} =$change in length;
${l}_{0} =$original length (at 22°C);
$\alpha =$expansion coefficient;
$\Delta T =$change in temperature.
$\frac{0.78}{1000} = {l}_{0} \cdot \alpha \cdot \left(35 - 22\right)$
${l}_{0} = 4.545 m$