Question

A spring has a spring Constant, k=90N/m calculate the extension of the spring when 0.45J of work are done stretching it?

Answer 1

Given:

$k=90\;\rm N/m$

$W=0.45\;\rm J$

The work done by a stretched spring

$$W=\frac{kx^2}{2}$$

Hence, the stretching

$$x=\sqrt{2W/K}=\sqrt{2*0.45/90}=0.1\:\rm m$$