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Homework Help: Help with some physics

  1. Feb 25, 2004 #1
    This is the scenario.


    A good guy and a bad guy crash their rocketships. The place has virtually no friction and no air. They fall into a ditch, and they can't climb out (because there is no friction). They CAN get out, but only one at a time. If the good guy gets out first, then he'll probably help the bad guy get out. If the bad guy gets out first, then he might not help the good guy. So how can they get out?


    I think Newton's laws would be useful in solving this...but otherwise i am VERY clueless. i need to turn this in tomorrow, PLEASE HELP!
  2. jcsd
  3. Feb 26, 2004 #2
    They can't get out b/c if they get out, they will suffocate in space, as you said there is no air in space.
  4. Feb 26, 2004 #3


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    Easy answer - repair their spaceships.

    Here's my guess.

    Have the two stand face to face, with a small lateral displacement from each other (so they don't collide painfully later on.)

    Now, push off.

    In the idealised environment of the frictionless ditch, the two will go up on one side of the ditch, slide down again, slide up on the other side of the ditch... With little friction, energy is always conserved.

    Now, have the two push each other whenever they have just passed eg. at this point.


    Newton's third law means that this impulse will increase the two's relative speed at this moment. With each push, then, the height reached by their sliding will increase, until one of them is out of the ditch.

    Then the battle of good vs evil may continue.
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