# Conservation of Energy

1. Mar 4, 2009

### RileyAllen

1. The problem statement, all variables and given/known data
A 0.570-{\rm kg} wood block is firmly attached to a very light horizontal spring(k=180 N/m). It is noted that the block-spring system, when compressed 4.4 cm and released, stretches out 1.7 cm beyond the equilibrium position before stopping and turning back.
What is the coefficient of kinetic friction between the block and the table?

2. Relevant equations
F=uk*k*x
F=mg

3. The attempt at a solution
uk=mg/(k*x)
I don't know what x is, and even still I don't know if that is the correct way to do the equation.

Any help would be greatly appreciated.

2. Mar 4, 2009

### Delphi51

x is the compression, 4.4 cm. Or the distance of stretch.
It looks like an energy question to me. Something like this:
energy stored in compressed spring = work done against friction + energy stored in stretched spring
I don't see the energy of a spring formula in your list: E = 1/2k*x^2

3. Mar 4, 2009

### RileyAllen

I ended up solving this one. Thanks for replying though!