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Homework Help: (101)Conservation of linear momentum

  1. Mar 1, 2008 #1
    [SOLVED] (101)Conservation of linear momentum

    1. The problem statement, all variables and given/known data
    A 86.7 kg man is standing on a frictionless ice surface when he throws a 0.1 kg book at 11.2 m/s. With what speed does the man move across the ice as a result?

    2. Relevant equations
    Since the momentum of the thrown book must equal that of the man in the opposite direction, m1v1=m2v2, or so I thought.

    3. The attempt at a solution

    I solved for the momentum of the book (.1)(11.2)=1.12 and then set that equal to the man*v

    So... 1.12=86.7v, v=.0723

    But thats was incorrect. So, no credit on my webassign homework but I would still like to understand how to solve it. Can someone help me out?
  2. jcsd
  3. Mar 1, 2008 #2


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    When I divide 1.12 by 86.7, I get 0.01291811 ;-)
  4. Mar 1, 2008 #3
    UGH! you're completely right... I mustve just been to antsy with the ANS key on my calculator.... how irritating. But my reasoning is sound I assume?
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