Question

A copper telephone wire has essentially no sag between poles 36.0 m apart on a winter day when the temperature is −20.0°C. How much longer is the wire on a summer day when the temperature is 34.0°C?

Answer 1

Answer:

The extension is  $\Delta L = 0.033 \ m$

Explanation:

From the question we are told that  

     The length of the wire on a winter day is    $L_w = 36.0 \ m$

      The temperature on the winter day is  $T_w = -20.0 ^o C$

      The temperature on a summer day is  $T_s = 34.0 ^0 C$

The the extension of the wire on a summer day is mathematically represented as

          $\Delta L = \alpha L_w [T_s - T_w]$

Where  

      $\alpha$ is the  coefficient of linear expansion of copper with a values $\alpha = 17 *10^{-6}$

substituting value  

      $\Delta L = 17 *10^{-6} * 36.0 [34 - [-20]]$

      $\Delta L = 0.033 \ m$