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Homework Help: Child on Slide

  1. Oct 8, 2009 #1
    1. The problem statement, all variables and given/known data
    A 25.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 19.00 m. When she is partway down the slide, at a height h2 of 6.00 m, she is moving at a speed of 9.10 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.).

    2. Relevant equations

    3. The attempt at a solution
    This question has something to do with change in potential energy and kinetic energy, but i am not sure where to go.
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Oct 8, 2009 #2


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    Homework Helper

    You are not showing any attempt. Before attempting the problems of this type, you must have gone through conservation of energy in freely falling body. Why don't you apply that?
  4. Oct 8, 2009 #3
    I have found potential energy at the top of the system (Pe=mgy). I have also found kinetic energy at the lower point (Ke=.5mv^2). It would make sense to take the difference, but I have already tried this method.
  5. Oct 8, 2009 #4
    Without friction, total energy is conserved. Which means the sum of your kinetic and potential energies should be equal at any two points taken. Are you sure you're including all forms of energy for the second point?
  6. Oct 8, 2009 #5
    I was able to find the answer! Thanks for the tips!
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