Spring Potential

jimmy42

If I have a spring connected to a roof with a natural length of l, then the spring potential at any point can be given as

0.5k(x-l)^2.

Assuming the datum is at the roof.

If the datum is at the natural length of the spring then the equation is

0.5kx^2+c

The trouble I have is to dertmine c. Could anyone give some tips on that?

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



2. Relevant equations



3. The attempt at a solution