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Homework Help: Hockey Puck (Momentum)

  1. Oct 7, 2008 #1
    Hello,

    Q.) A hockey puck moving at 0.48 m/s collides elastically with another puck that was at rest. The pucks have equal mass. The first puck is deflected 39° to the right and moves off at 0.35 m/s. Find the speed and direction of the second puck after the collision. Make sure the speed is in m/s and direction in terms of degrees

    A.) The way i tried solving this problem is below:

    m1=m2

    Hockey Puck #1:
    p=p(final)-p(initial)
    =m1(vfinal-vinitial)


    Hockey Puck #2:
    =m2(vfinal-vinitial)


    p1=p2

    m1(v1final-v1initial)=m2(v2final-v2initial)

    Both the masses cancel out..... we have the following:
    v1initial=.48
    v1final= .35cos39
    v2initial=0

    Plug in formula and get v2final=-.21 since it's going to the left....but this answer is wrong.

    I tried 39° for the second puck since they both weight the same but this is wrong as well.


    Please i don't know why i'm getting this wrong. Any help will be appeciated :smile:
     
  2. jcsd
  3. Oct 8, 2008 #2
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