Conservation of energy of a spring problem

[Amar.alchemy]

Homework Statement

A 1.20-kg piece of cheese is placed on a vertical spring of negligible mass and force constant k = 1800 N/m that is compressed 15.0 cm. When the spring is released, how high does the cheese rise from this initial position? (The cheese and the spring
are not attached.)

Homework Equations

Conservation of Energy equation.

The Attempt at a Solution

Actually what i want to know is, while calculating the gravitational potential energy, should i include 15.0 cm(ie distance by which spring is compressed) or should i start from the point from where it leaves the spring?? kindly clarify.

 

[Doc Al]

The initial position is the compressed position--measure changes in gravitational PE from that lowest point. (Measure the final height from that point as well.)

 

[Amar.alchemy]

Thanks Doc :-)