# Thread: find the work done by stretching a spring..

1. ## find the work done by stretching a spring..

im not sure if i did this problem right, something tells me i didnt do it right...could you check my work? thanks in advance.

IMG.pdf

2. the key here is to treat the natural length of the spring (no stretch) as $x = 0$

stretching the spring 5 cm beyond its natural length ...

$k = \frac{F}{x} = \frac{30 \, N}{.05 \, m} = 600 \, \frac{N}{m}$

work done to stretch the spring 10 cm beyond its natural length ...

$W = \int_0^{0.1} 600x \, dx$

work done to stretch the spring from 20 cm to 30 cm (from 10 cm to 20 cm beyond its natural length) ...

$W = \int_{0.1}^{0.2} 600x \, dx$