# Homework Help: Okay, so this is probably very easy, just checking the solution

1. Sep 23, 2009

1. The problem statement, all variables and given/known data
Okay guys, I'm new here, and this problem just annoyed me because I believe it's very simple, but it looks like it could be more complicated.

Two large crates, with masses 640 kg and 490 kg, are connected by a stiff, massless spring (k=8.1 kN/m) and propelled along an essentially frictionless, level factory floor by a force applied horizontally to the more massive crate. If the spring compresses 5.1 cm from its equilibrium length, what is the applied force?

2. Relevant equations

I think it's just this one: Fspring = -k*x

3. The attempt at a solution

Okay, the only thing that makes it sound at all complicated is that the crates are different masses, and that they talk about mass at all. But I want to say it's just 8.1*(.051) to get kN. Is that it? Or should I take in to account the masses of the boxes. In which case I'm not quite sure where to go.

2. Sep 23, 2009

### Gear300

Looks like you got it.