# Gravitational PE, Elastic PE

1. Oct 24, 2011

### lefthand

i need help with this problem. i have no idea how to do this.

A 1.41 kg object is held 1.38 m above a relaxed, massless vertical spring with a force constant of 288 N/m. The object is dropped onto the spring.
(a) How far does the object compress the spring?
1 m

(b) Repeat part (a), but now assume that a constant air-resistance force of 0.872 N acts on the object during its motion.
2 m

(c) How far does the object compress the spring if the same experiment is performed on the moon, where g = 1.63 m/s2 and air resistance is neglected?
3 m

2. Oct 24, 2011

### vela

Staff Emeritus
It's pretty obvious you just put down random answers and haven't made a serious attempt at solving the problem, which is why you're not getting any responses.

What physical principle do you think applies here? Why do you think it does? What are some of the relevant equations?

3. Oct 24, 2011

### lefthand

i didn't put those answer. i really don't know how to do this problem or where to start

4. Oct 24, 2011

### Redbelly98

Staff Emeritus
What equations are there that have something to do with energy? What equations are there that have something to do with springs? Looking at these would be a good starting point.

If you don't actually know the equations, look in your textbook for them.