# Homework Help: Conservation of momentum, confused about variables

1. Sep 11, 2009

### shredder666

1. The problem statement, all variables and given/known data
In a conservation of momentum lab, two objects were collided together, velocity before and after the collision were measured.

The problem asks how the momentum compares before and after

I'm really confused about the variables here...

In the hypothesis it asks to relate the momentum of a system before and after collision into a "if...manipulated is... then...responding is" format

How do I write it into an if...then... format?!?

I realize that the independent/manipulated variable is the initial given velocity but I'm confused about the responding variable, Is it the after crash velocity or the after crash momentum?

2. Sep 11, 2009

### rl.bhat

The change in momentum of colliding bodies during collision depends on their masses and their initial velocities. So compare the momentum of each body taking into account its mass and velocity.

3. Sep 11, 2009

### shredder666

well I realize that but I'm more concerned about the responding variable

Is it the velocity or the momentum?

4. Sep 11, 2009

### rl.bhat

Both.

5. Sep 12, 2009

### shredder666

well... I have to choose from 1 of them... which would be a better answer?

6. Sep 12, 2009

### rl.bhat

Momentum,. Because it takes into account of both mass and velocity.

Last edited: Sep 12, 2009