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# Oblique Impact watch

1. Hey

I need some help with the following question:

Two equal unifrom smooth spheres mass m are at rest in contact with each other on a smooth horiz table. A third unifrom smooth sphere of same radius but mass 3m moves with speed u on table in direction perp to line of centres of the other 2 spheres and strikes them simultaneously. The coeff of restitution btwn any 2 spheres is e. find the speeds of the three spheres after impact.

Would it be right to assume that the two spheres mass m would both move off in direction 45 deg to the line of centre? This is what i assumed when coming up with the equations. Any ideas of how to deal with the motion of the two spheres mass m after collision...

The answer is (root 3)/3 *(1+e)u for the two spheres but im getting 3(root 2)/8 instead of the (root 3)/3

Thanks
2. (Original post by azamally)

Would it be right to assume that the two spheres mass m would both move off in direction 45 deg to the line of centre?
Thanks
No, it wouldn't.

Draw a diagram of the three spheres at the point of impact, and the triangle connecting all three centres; it should be clear which direction they go in.
3. (Original post by ghostwalker)
No, it wouldn't.

Draw a diagram of the three spheres at the point of impact, and the triangle connecting all three centres; it should be clear which direction they go in.
Looks like an equilateral there. Thanks Ghostwalker!

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