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Homework Help: Estimate the power required to operate the tow

  1. Sep 4, 2007 #1
    1. The problem statement, all variables and given/known data
    A ski tow is operated on a 20 degree slope of lenth 300m. The rope moves at 12.0km/h, and power is provided for 70 riders at one time with an average mass per rider of 65kg. Estimate the power required to operate the tow.

    2. Relevant equations
    P = Work / t
    P = F * v

    3. The attempt at a solution
    60kg * 70 riders = 4550kg
    Solving for time:
    V = 12km/h = 3.33m/s

    t = d / V
    = 300m / 3.33m/s
    = 90.09s

    P = (F * d) / t
    P = ((4550kg)(9.8m/s^2)( 300m))/(90.09s)
    = 148484.8485 watts

    I dont see what is the angle used for
    maybe for another component of force? or is it no use?
    Last edited: Sep 4, 2007
  2. jcsd
  3. Sep 4, 2007 #2


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    Homework Helper

    You need the acceleration along the slope to be zero to keep the riders moving at a constant velocity along the slope... The ski tow exerts a force along the slope.

    Also, you can directly use F*v for power, instead of using time and distance...
  4. Sep 4, 2007 #3
    0 = F - wsin(theta)
    F = (4550kg)(9.8m/s^2)sin(20) << so force

  5. Sep 5, 2007 #4


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    Homework Helper

    yup. then using this force F*v gives power.
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