# Oblique impact of smooth spheres?

1. Dec 2, 2007

1. A sphere of mass m impinges obliquely on a sphere of mass M, which is at rest. The coefficient of restitution between the spheres is e. Show that if m=eM, the directions of motion after impact are at right angles

2. Coefficient of restitution -

3. I really dont think I have a clue with this one, so far I have taken e and substituted it into m=eM to give

m = M x V$$_{}2f$$-V$$_{}1f$$$$/$$V$$_{}1$$

Can anyone give me any clues as to where to go next or am I going completely wrong with what I have?

Thanks in advance for any help

2. Dec 2, 2007

### dlgoff

Have you tried to draw a vector representation of your problem? Try this and make use of the conservation of momentum.

3. Dec 2, 2007

This is what I have for the problem,

Do I have the right idea of what the collision looks like?

And how would I use the momentum conservation here, as in U1 (speed of m before) = V2 (speed of M after)?

4. Dec 2, 2007

### dlgoff

Well, that's not exactly what I had in mind.

Could you read over this Elastic Collisions artical and let me know if it helps?

5. Dec 2, 2007