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Homework Help: The Force Exerted by the Ground on a Parachuter

  1. Sep 21, 2008 #1
    1. The problem statement, all variables and given/known data
    A 35.5 kg parachutist lands moving straight downward with a speed of 3.85 m/s.
    (a) If the parachutist comes to rest with constant acceleration over a distance of 0.700 m, what force does the ground exerts on her?

    Variables: Vo, Vf, F, m, a, x
    Known: Vo=3.85 (I think the problem means this as the initial)
    m=35.5 kg
    Vf=0 (don't quite understand the problem)
    x=.7 m

    2. Relevant equations
    Possibly Vf^2=Vo^2+2ax

    3. The attempt at a solution
    I used Vf^2=Vo^2+2ax, and I got 10.5875 m/s^2, multiplied that by 35.5 kg, and I got 375.86 N. WebAssign says the answer is wrong.
  2. jcsd
  3. Sep 21, 2008 #2
    I figured it out. Apparently that is just the force required to stop the object--you must also factor in the weight.
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