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Skier work physics problem

  1. Jun 18, 2007 #1
    A skier of mass 72.6 kg is pulled up a slope by a motor-driven cable. How much work is required to pull the skier 64.3 m up a 37.2 degrees slope? (assumed frictionless) at constant speed of 63.2 m/s.

    For this question, would I just use the equation W = 1/2 mv squared?

    Thank you so much!
     
  2. jcsd
  3. Jun 18, 2007 #2
    it is gaining height too, so PE=mgh is needed too
     
    Last edited: Jun 18, 2007
  4. Jun 18, 2007 #3
    "...at constant speed of 63.2 m/s."

    No--the equation K = (1/2)mv^2 is for kinetic energy. In your problem, the skier's kinetic energy remains the same because his speed remains the same. Only his gravitational potential energy (U = mgh) changes. Since the work done pulling the skier up does not go to changing his kinetic energy, it must have gone to changing his gravitational potential energy, right?
     
    Last edited: Jun 18, 2007
  5. Jun 18, 2007 #4
    Oh I see! Thank you very much for your help!
     
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