# What does this equation mean? Physics Work.

1. Oct 19, 2011

### DavidAp

This equation is given on my equation sheet for Work but I'm not sure what the sub s stands for. This isn't really a homework question but I'm asking it in this thread because it may help me with my homework. Can someone explain this equation to me? Thanks!

Fs = -kx

Some sort of Force is equal to negative kinetic energy times displacement in the x direction? What force, when do I use this equation?

2. Oct 19, 2011

### NewtonianAlch

Force exerted on spring, possibly.

It's the equation that you have probably encountered in relation to Hooke's law. Where k is the spring constant and x is the distance stretched/travelled.

3. Oct 19, 2011

### DaveC426913

Fs simply means the Force of s - whatever s is. The s is arbitrary and simply denotes what F it is referring to.

If you had air and water pressing on a bladder, you might use Fa and Fw

4. Oct 19, 2011

### HallsofIvy

Staff Emeritus
Yes, this is Hooke's law- the force due to a spring is proportional to the distance it is stretched or compressed. F is the force, and x is the amount of stretch or compression. "k" is not "kinetic energy", it is the constant of proportionality. If F is in Newtons and x is in meters, then k is measured in Newtons per meter.