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Skier down a hill

  1. Sep 12, 2011 #1
    1. The problem statement, all variables and given/known data

    A 50kg skier skis directly down a frictionless slope angled 16* to the horizontal. Assume the skier moves at a negative x direction. A wind force with component Fx acts on the skier.

    What is Fx if the skier's velocity magnitude is constant?

    2. Relevant equations

    3. The attempt at a solution

    I really have no idea. I assume Fx is equal to the force the skier exerts "on the air" so F = ma on the skier.

    But I am utterly confused when they say velocity is constant. He is going down the slope due to gravity, how could his velocity be constant? It makes no sense to me.
  2. jcsd
  3. Sep 12, 2011 #2


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    Gold Member

    The negative x direction is the direction the skier goes. There are two forces which act in the x direction on the skier, -sin(16)*m*g and F_x, they are equal and opposite.
  4. Sep 13, 2011 #3
    How would I adjust that if the skier's velocity is increasing 10m/s/s?

    -sin(16)(5)(9.8 + 10t)
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