# Spring max depression

1. Oct 22, 2004

### quick02si

Ok I was wondering if someone could help me with this problem i'm not sure how to set uo the problem in order to solve it using kinetic and potential energy. Thank you heres the question.

An 80.0-kg man jumps from a height of 2.50 m onto a platform mounted on springs. As the springs compress, he pushes the platform down a maximum distance of 0.240 m below its initial position, and then it rebounds. The platform and springs have negligible mass.
What is the man's speed at the instant he depresses the platform 0.120 m?
If the man just steps gently onto the platform, what maximum distance would he push it down?

2. Oct 22, 2004

### Sirus

You know $F_{spring}=-kx$ and $E_{elastic potential}=\frac{1}{2}kx^{2}$. Can you go from there? Try using free-body diagrams and thinking about the transfer of energy here.