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Homework Help: Can you confirm a simple Physics Velocity Question?

  1. Dec 9, 2009 #1
    1. The problem statement, all variables and given/known data

    Object a Mass 6kg moving velocity 5m/s is followed by a second object mass 8kg velocity 8m/s in the same straight line.

    If the two objects are joined together after collision and move in the original direction, calculate heir common velocity.

    3. The attempt at a solution

    Now have either:

    6x5 - 8x8 = 14V

    -34 = 14V

    -34/14 = V

    V = -2.42m/s

    or 5x6 + 8x8 = 14V

    94 = 14V

    94/14 = V

    V = 6.71m/s

    Which one is right?

    Thanks in advance
  2. jcsd
  3. Dec 9, 2009 #2
    The second one is right because both of the objects are moving in the same direction hence you would ADD the initial momentum of each mass.
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