Question

If a metal wire is 4m long and a force of 5000n causes it to stretch by 1mm, what is the strain?

Answer 1

Answer:

$2.5\cdot 10^{-4}$

Explanation:

The strain is defined as the ratio of change of dimension of an object under a force:

$S=\frac{\Delta L}{L_0}$

where

$\Delta L$ is the change in length of the object

$L_0$ is the original length of the object

In this problem, we have $L_0 = 4 m$ and $\Delta L=1 mm=0.001 m$, therefore the strain is

$S=\frac{\Delta L}{L_0}=\frac{0.001 m}{4 m}=2.5\cdot 10^{-4}$