Finding elastic constant given mass and elongation

1. Feb 26, 2009

Prio

1. The problem statement, all variables and given/known data
I'm doing a lab where a known mass is suspended by a spring. All that is known is the mass of the weight used and the length of the elongation of the spring, and I need to find the elastic potential energy of the spring and the spring constant, K.

2. Relevant equations
(formatted text links aren't clicking for me?)
Elastic PE = 1/2Kx^2--x normally applies to the elongation of the spring though it is extending in the y direction in this case

Gravitational PE = 9.81mh

GPE + EPE = Total PE/KE (energy is assumed to be conserved)

3. The attempt at a solution
The problem is I have two variables and no way I can see to substitute for one of them to simplify the equation, so I don't know how to isolate a spring constant or the elastic potential energy.

2. Feb 26, 2009

Delphi51

You need the other spring formula, F = kx.

3. Feb 26, 2009

Prio

Ah, that should help. is that force found with Mass*g*x?
Thanks for the help thus far.

4. Feb 26, 2009

Delphi51

The F is mass*g.
Solve for k.

5. Feb 26, 2009

Prio

lol you're right-- after I thought about it, I realized it was just m*g. I'll be able to finish it up , and now I'm sure you want to get to some more questions so have a good night;)