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Homework Help: The Skier and the Tow Bar

  1. Feb 3, 2009 #1
    1. The problem statement, all variables and given/known data
    A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 24.0° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 61.9 kg, and the coefficient of kinetic friction between the skis and the snow is 0.140. Calculate the magnitude of the force that the tow bar exerts on the skier.

    2. Relevant equations


    3. The attempt at a solution


    I thought I was doing everything right but I got the wrong answer so I was hoping for a little guidance thanks!
  2. jcsd
  3. Feb 4, 2009 #2
    Your 247N value looks correct for the Normal force.

    I don't know what that mgcos(theta) business is all about.

    You already know to multiply the normal force by the coefficient of friction to get the force you need to overcome.

    If the skier is moving up at constant speed then the towbar force is equal to this
  4. Feb 4, 2009 #3
    Error in previous post.

    The force mgcos(theta) is of course operating down the slope and helps the frictional force to oppose the towbar force, so...

    TowbarForce = FrictionalForce + SkierWeightDownhillComponent
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