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Homework Help: Work done by Friction

  1. Oct 13, 2004 #1
    Hi everyone. I have another problem that is just stumping me. I posted this earlier and still can't understand it. Here it is...

    A 1-kg ball starting at h = 6.1 meters slides down a smooth surface where it encounters a rough surface and is brought to rest at B, a distance 18.3 meters away. To the nearest joule what is the work done by friction?

    Imagine the ball starting on top of a waterslide, sliding down with no friction, and then coming down onto the straight path that slows you down. I can find the Potential Energy of the ball, but don't know where to go from there! Pls help!
  2. jcsd
  3. Oct 13, 2004 #2
    Law of conservation of energy :
    Total energy in the beginning=Total energy in the end
    [tex]mgh= W_f[/tex]
    The potential energy of the ball has been transformed to heat etc due to the work done by friction.
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