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Homework Help: Roller Coaster Problem with Friction

  1. Oct 20, 2008 #1
    1. The problem statement, all variables and given/known data
    Suppose the roller coaster in the figure (h1 = 35 m, h2 = 13 m, h3 = 20) passes point A with a speed of 2.70 m/s. If the average force of friction is equal to one sixth of its weight, with what speed will it reach point B? The distance traveled is 35.0 m.

    2. Relevant equations
    Work force of friction = [1/2mv2^2-1/2mv1^2] + [mgh2-mgh1]

    3. The attempt at a solution
    I took 1/6(9.8m/s^2)(35m) = [1/2v2^2-1/2(2.7m/s)^2] + [(9.8m/s^2)(13m)-(9.8m/s^2)(35m)] and got 23.5m/s which is not correct...what am I doing wrong?
    Last edited: Oct 20, 2008
  2. jcsd
  3. Oct 20, 2008 #2
    Please help I am really frustrated with this one!
  4. Oct 20, 2008 #3
    I figured it out, I had the change in height incorrect. V^2 = 2(9.8m/s^2)(35m) + (2.7m/s)^2 - 1/6(9.8m/s^2)(35m)
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