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Homework Help: Calculation loss of energy due to friction?

  1. Mar 19, 2010 #1
    1. The problem statement, all variables and given/known data

    http://i43.tinypic.com/i1bq1i.jpg
    I need help with number 9

    2. Relevant equations

    Wnet=change in KE
    Wnc=Change in Energy

    3. The attempt at a solution
    I haven't been able to get the answer marked by the computer.
    I tried Fs(h*cos15)=.5mv^2-mgh
    and that is way off the anwser
     
  2. jcsd
  3. Mar 19, 2010 #2

    ideasrule

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    Homework Helper

    Can you explain that equation? I don't understand what F and s are, or how you derived Fs(h*cos15).
     
  4. Mar 19, 2010 #3
    sorry I meant that F(k) which is the force due to kinetic friction.
    The equation for work is FDcos(theta). They gave use the height so I calculated the distance of the slope by Pythagorean theorem which gives cos(15)*the height.
     
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