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Inelastic collisions in 2 dimensions

  1. Jul 15, 2013 #1
    I am unsure how to proceed with this problem because it is asking for the final velocity of one of the two objects given the initial velocities. This is an inelastic collision not a completely inelastic collision, which means the two objects do not stick together. The book makes a distinction between the two.

    If you can give me some hints as how to proceed it would be truly helpful.

    1. The problem statement, all variables and given/known data

    A 0.800 kg target slides along the ice at 3.0 m/s [W], when it is hit by a 20.0 g arrow
    moving at 260 m/s [N], as part of a show. Find the final velocity of the target after the
    inelastic collision.


    let east and north be positive

    m1 = 0.800 kg
    v1 = 3.0 m/s [W]
    m2 = 0.0200 kg
    v2 = 260 m/s [N]

    find v1f

    2. Relevant equations


    m1v1i + m2v2i = m1v1f + m2v2f

    3. The attempt at a solution

    The question is asking for the final velocity of the target which is find v1f
    This is an inelastic collision, not a completely inelastic collision, this means the arrow will not stick to the target.

    vix = -3.0 m/s
    viy = 260 m/s


    Pxi=(0.8)(-3)=-2.4 Ns
    Pyi=(0.02)(260)=5.2 Ns
    Last edited: Jul 15, 2013
  2. jcsd
  3. Jul 15, 2013 #2


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    If the arrow does not stick to the target, then there is not enough information to solve the problem. I suspect that even though the problem does not say completely inelastic, that is what you should assume (unless other information is given).
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