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Homework Help: Help with momentum physics problem

  1. Jul 3, 2016 #1
    Ball A, which weighs 2 kilograms, is moving at 0.5 meters/second and strikes stationary Ball B at the direct center of the ball.
    Ball B, which weighs 3 kilograms, moves off at 0.3 meters/second and in the same original direction Ball A was moving. Ball A continues to move forward, but only at 0.1 meters/second. Is momentum conserved? Explain.

    I don't even know where to start, or what to do so could I have some help with this?
  2. jcsd
  3. Jul 3, 2016 #2
    The momentum of the system is conserved if it's the same before the strike and after...
    What's the momentum before?
    What about after?
  4. Jul 4, 2016 #3
    The system consists of two bodies: ball A and ball B
    All the movements are performed along one axis: OX. Let the positive direction coincide with the direction of ball A movement.
    Then, the momentum before the strike
    P1 = mAvA + mBvB
    vA = 0.5 m/s, vB = 0
    The momentum after strike
    P2 = mAuA + mBuB
    uA = 0.1 m/s, uB = 0.3 m/s

    So, the conclusion is clear but still up to you)
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