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Homework Help: Determine the Gravitational potential energy

  1. Nov 5, 2005 #1

    A Skier with a mass of 65.0 kg. Including equipment, starts from rest and accelerates down a slope. The slope is 27.0 m higher at the top than the bottom. The work done on the skier by the kinetic friction is 1.20 x 10^4 J.

    How would I determine the Gravitational potential energy at the top slope relative too the bottom?

    Kinetic energy at the bottom?

    And the skiers speed at the bottom of the slope?
  2. jcsd
  3. Nov 5, 2005 #2
    The potential energy would just be mgh, with h = 27m.

    Then to find the kinetic energy at the bottom you would subtract the energy lost to friction from the potential energy.

    Once you have the kinetic energy, use (1/2)mv^2 = k, then solve for v to find the velocity.
  4. Nov 5, 2005 #3


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    P.E. = mgh (65kg)(9.81)(27m) = 17.22 kJ

    (P.E.)17.22kJ - (fs)12.0kJ = 1/2mv^2

    5.22kJ = 1/2mv^2 (K.E. bottom)
    Last edited: Nov 5, 2005
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