Calculating Potential Energy Stored in Springs

[vysero]

A mass of 10kg hangs from an ideal (massless) spring from the ceiling. The mass and spring are in static equilibrium, so there is no motion. If the spring has a spring constant k=1000N/m and g = 10 m/s/s, what is the (potential) energy stored in the spring?



PE = mgh and KE(of spring)= 1/2kx^2 and maybe hooks law



Kind of stumped.

I am not sure how to go about this problem as I am not sure if it is a trick question. Since PE = mgh and there is no height here would the PE = 0? If I set PE = 1/2kx^2 I have one equation with two unknowns which does not help me. I want to say its a conservation of energy problem but I am not sure. Please help me understand.

 

[haruspex]

Since PE = mgh and there is no height here would the PE = 0?

It asks for the PE stored in the spring, not gravitational PE.
But you do need to work out the spring extension.

 

[vysero]

Ah okay so:

100N = 1000(x), x = .1

and (1/2)(1000)(.1)^2= 5 joules, is that right?

 

[haruspex]

Looks right.