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Homework Help: Momentum- HELP

  1. May 4, 2008 #1
    Momentum- HELP!!!!!

    A 40kg child stands at one end of a 70kg boat that is 4m in length. The boat is initially 3m from the pier. The child notices a turtle on a rock at the far end of the boat and proceeds to walk to that end to catch the turtle. Neglecting friction between the boat and the water
    a) Describe the susequent motion of the system (child+boat).
    b) Where will the child be relative to the pier when he reaches the far end of the boat?
    c) Will he catch the turtle? (Assume he can reach out 1m from the end of the boat.)

    I don't really know how to do any of this. I don't even know where to start. Please help!
  2. jcsd
  3. May 4, 2008 #2
    The key to this situation is that friction is negated. What would happen if you tried to walk forward on ground that has no friction? How do your feet make you move forward? Try and see the situation from a outside reference point. What would the boy look while walking if you were watching from the dock?
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