Conservative Forces and Potential Energy (Problem 23)

A pogo stick has a spring with a force constant of $2.50\times {10}^4\text{ N/m}$, which can be compressed 12.0 cm. To what maximum height can a child jump on the stick using only the energy in the spring, if the child and stick have a total mass of 40.0 kg? Explicitly show how you follow the steps in the Problem-Solving Strategies for Energy.