- #1

fubag

- 105

- 0

**[SOLVED] Bouncing Electrongs**

Two electrons, each with mass m and charge q, are released from positions very far from each other. With respect to a certain reference frame, electron A has initial nonzero speed v toward electron B in the positive x direction, and electron B has initial speed 3v toward electron A in the negative x direction. The electrons move directly toward each other along the x-axis (very hard to do with real electrons). As the electrons approach each other, they slow due to their electric repulsion. This repulsion eventually pushes them away from each other.

What is the minimum separation (r_min) that the electrons reach?

Express your answer in term of q, m, v, and k.

All I understand so far is that both electrons are moving at the same nonzero speed in the same direction.

I need help starting this question. I understand that U1 + K1 = U2 + K2 for conservation of energy.

I also understand that U = kqQ/r for a point charge. So in this case I believe U1 = -ke^2/r, and then K1 = mv^2/r. Also I believe U2 = -ke^2/r and K2 = -3mv^2/r.

Please tell me if these are correct assumptions, and what I need to do next.

Thanks!