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Homework Help: Energy probl

  1. Nov 2, 2008 #1
    1. The problem statement, all variables and given/known data

    75 kg boy, starting from rest, slides down a 30 degrees hill htat is 70 m long. He arrives a thet bottom with a speed of 15 m/s. How much thermal energy has been shared btwn the surface of the hill and the seal of his pants

    2. Relevant equations
    d=(vf2-vi2)/2a
    KE=1/2Mv2
    change of ENERGYsystem=constant
    PEi +KEi=PEf + KEf
    PE=Mgh



    3. The attempt at a solution
    I have no clue to figure this out....please help by explaining the steps..Many thanks!
     
  2. jcsd
  3. Nov 3, 2008 #2

    LowlyPion

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    Homework Helper

    Figure what his PE was. Then figure what his KE is at the bottom. The difference went into warming his behind.
     
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