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Homework Help: Skateboard problem

  1. Oct 30, 2004 #1
    Matt is gliding on his skateboard at 4.00 m/s. He suddenly jumps backward off the skateboard, kicking the skateboard forward at 8.00 m/s. Matt's mass is 50 kg and the skateboard's mass is 7 kg. How fast is Matt going as his feet hit the ground?

    I have no idea where to begin. Should I first find the change in momentum?
    Last edited: Oct 30, 2004
  2. jcsd
  3. Oct 30, 2004 #2
    All you have to do is use conservation of momentum:

    [tex]p_{final} = p_{initial}[/tex]
  4. Oct 31, 2004 #3
    Is this right

    v_f(50kg + 7kg) = 50kg*4m/s + 7kg*4m/s
    v_f = 4.49m/s ?
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