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3D elastic collisions of spheres: angular momentum

  1. Jun 30, 2010 #1
    Hi, I'm helping my friend with a space combat game he is programming. What I'm trying to figure out is how to model the collisions between spheres in 3D.

    So far I've figured out how to calculate final velocities of 2 colliding spheres using conservation of linear momentum. I found a http://www.wheatchex.com/projects/collisions/" [Broken] which gives me this formula:

    v1f = v1i - ((m2c)/(m1 + m2))(1 + e)n
    v2f = v2i + ((m1c)/(m1 + m2))(1 + e)n


    v1i = the initial velocity of object 1
    v2i = the initial velocity of object 2
    m1 = the mass of object 1
    m2 = the mass of object 2
    e = the coefficient of restitution (e = 1 for elastic collision)
    n = normal unit vector drawn from object 1 to object 2
    c = n . (v1i - v2i)

    My question is, using conservation of angular momentum, how would I work out the angular velocities of spinning spheres after they collide? How much spin is transferred from one sphere to another? How much angular momentum, if any, would be converted to linear momentum?

    Thanks for your time
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jun 30, 2010 #2


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    Science Advisor

    Take a look at this thread, where we discuss something similar, that resulted eventually in a working program.
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