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Homework Help: Oblique impact of smooth spheres?

  1. Dec 2, 2007 #1
    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 - 442cb57fc9daffed79a534632d0a5aad.png

    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[tex]_{}2f[/tex]-V[tex]_{}1f[/tex][tex]/[/tex]V[tex]_{}1[/tex]

    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. jcsd
  3. Dec 2, 2007 #2


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    Have you tried to draw a vector representation of your problem? Try this and make use of the conservation of momentum.
  4. Dec 2, 2007 #3
    This is what I have for the problem,

    http://img156.imageshack.us/img156/2310/questioncb9.jpg [Broken]

    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)?
    Last edited by a moderator: May 3, 2017
  5. Dec 2, 2007 #4


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

    Could you read over this http://instruct.tri-c.edu/fgram/web/elastic.htm" [Broken] and let me know if it helps?
    Last edited by a moderator: May 3, 2017
  6. Dec 2, 2007 #5
    Ah, that article was exactly what I needed, thanks for your help :D
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