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Homework Help: Fun ski area problem

  1. Oct 12, 2007 #1
    [SOLVED] Fun ski area problem

    1. The problem statement, all variables and given/known data

    A T-bar tow is planned in a new ski area. At any one time, it will be required, to pull a maximum of 82 skiers up a 609-m slope inclined at 14.1° above the horizontal at a speed of 2.37 m/s. The coefficient of kinetic friction between the skiers skis and the snow is typically 0.0600. As the manager of the facility, what motor power should you request of the construction contractor if the mass of the average skier is 66.0 kg. Assume you want to be ready for any emergency and will order a motor whose power rating is 54.0 percent larger than the bare minimum.

    2. Relevant equations

    N = mg cosθ
    F = mg (sinθ + μcosθ)
    Po = Fv

    so solve for P in: P = (Po + .54 Po)N

    3. The attempt at a solution

    P=((66.0*82*g)*(sinΘ + .06cosΘ))*2.37) +
    (.54)*((66.0*82*g)*(sinΘ + .06cosΘ))*2.37)

    I then multiply the answer for P times (66.0*g*cosΘ)
    Answer=3.67x10^7 W

    The program we submit our answers to says that my answer is wrong. I don't know what I am doing wrong. Thank you for any help!
  2. jcsd
  3. Oct 12, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This seems reasonable.

    Why?? P is your answer.
  4. Oct 12, 2007 #3
    Our professor went over the problem in class and said we should multiply it by N and N is mg*cos(theta). He said that when we figure out N we should use the mass of only one skier.
  5. Oct 12, 2007 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Sorry, but that makes no sense to me at all. It won't even have the correct units.
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