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Homework Help: A 2.0-kg ball is travelling east at 8.0 ~ Momentum

  1. Oct 29, 2012 #1
    A 2.0-kg ball is travelling east at 8.0 m/s when it has a perfectly elastic head-on collision with a 3.0-kg ball traveling west at 10.0 m/s. What are the final velocities of the two balls?

    Please help I don't know where to start
  2. jcsd
  3. Oct 29, 2012 #2
    You know momentum is conserved when bodies collide, start with the momentum principle:
    M1Vi + M2Vi = M1Vf + M2Vf

    And try another formula, which represents the conservation of kinetic energy:

    1/2(M1)(Vi)^2 + 1/2(M2)(Vi)^2 = 1/2(M1)(Vf)^2 + 1/2(M2)(Vf)^2
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