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Speed ratio

  1. Jul 6, 2008 #1
    Two children are facing each other. Child one has mass of 45kg and the other 65 kg. They push off one another and move in opposite directions. What is the ratio of child one's speed to child 2's?
    Answer choices:
    a 45:65
    b 45:110
    c 1:1
    d 65:45
    e cant tell from this info

    I don't know where to start, so I'm thinking the answer is e.
  2. jcsd
  3. Jul 6, 2008 #2


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    Consider conservation of momentum.
  4. Jul 6, 2008 #3


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    Surely part of the question has been left off. The children are on skates, so that they move frictionlessly? If so, as Hootenanny said, use conservation of momentum.
  5. Jul 6, 2008 #4
    thanks :)
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