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Easy Conservation of Energy (Skiing)

  1. Mar 4, 2009 #1
    Two snow-covered peaks at elevations of 3500 m and 3400 m are separated by a valley. A ski-run having a total length of 3000 m extends from the top of the higher peak to the top of the lower one. A skier starts from rest on the higher peak. With what speed will the skier arrive at the topof the lower peak if she glides down the hill as fast as possible without any initial push? Neglect friction.

    h1 = 3500 m
    h2 = 3400 m

    mgh1 = 0.5mv^2 + mgh2
    gh1 = 0.5v^2 + gh2

    v = sqrt(2g(h1-h2))
    v = 44.27 m/s
    Can anybody verify this with me? It looks good to me, but I did not use the information that the slope was 3000 m long. Is this unneccessary information or did I do something wrong?
  2. jcsd
  3. Mar 4, 2009 #2


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    Homework Helper

    "Neglect friction."

    That renders the length irrelevant.

    Looks OK to me.
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