# Homework Help: Electrostatic collision between two masses

1. May 25, 2013

### unscientific

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

I've done part (a) and (b) using conservation of momentum and energy..for part (c) I'm not sure how to find the minimum angle ∅. I have also worked out the velocities of m1 and m2 just before the collision as required in part (a).

I've done a sketch that shows something like:

I know that in the zero-momentum-frame the total momentum must be zero, so their momentum are aligned. (different masses results in them having different velocities, in order to ensure Ʃp = 0)

2. May 26, 2013

### Mandelbroth

Just for the math folk, let's use $\varphi$ rather than the empty set for our variable. :tongue:

You have the velocities of the two masses. Velocity is a vector. The question you need to ask yourself is "how do you find the angle between two vectors?"

You probably meant speed, in which case...how do you relate speed and velocity?

3. May 27, 2013

### unscientific

I know the answers to all your questions, but i'm not sure if they're helpful in this question...

4. May 29, 2013

bumpp