# Homework Help: Coefficient of friction of a spring

1. Nov 16, 2008

### reaperkid

1. The problem statement, all variables and given/known data

A 1676 g mass is on a horizontal surface with mu-k = 0.340, and is in contact with a massless spring with a force constant of 508 N/m which is compressed. When the spring is released, it does 9.17 J of work on the mass while returning to its equilibrium position. Calculate the distance the spring was compressed. Then find the velocity of the mass as it loses contact with the spring?

m = .1676 kg
muk = .34
k = 508 N/m
w = 9.17 J

2. Relevant equations

W = Fd
x = F/k
muk = Fk / Fn

3. The attempt at a solution

I'm not sure if I'm even on the right track or not.
But I tried using simultanious equations and I got
d = squareroot (9.17/508) = .13 m but that wasn't right.

2. Nov 17, 2008

### tiny-tim

Welcome to PF!

Hi reaperkid! Welcome to PF!

(have a mu: µ )
You haven't written the standard energy equation for a spring …

E = (1/2)kx2

(Your W = Fd gave you the wrong result, because you didn't integrate )