- #1

hiuting

- 23

- 0

## Homework Statement

I don't know when the work of a spring is negative, and when it's positive... When is the work of a spring negative and when is it positive?

## Homework Equations

W

_{sp}= -(1/2)(k)(xf

^{2}-xi

^{2})

## The Attempt at a Solution

I can get Wsp to be positive when the spring is stretch, but I want to know the theory behind it.