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Homework Help: Iceskating up a hill

  1. Dec 18, 2013 #1
    1. The problem statement, all variables and given/known data

    An iceskater weighing 69kg is gliding up an incline hill at 20 degrees.
    How high up does the skater make it when her initial velocity is 8,9m/s and the friction between her skates and the ice is 0,97N.

    2. Relevant equations

    mg(y) = m*g*cos(20)
    mg(x) = m*g*sin(20)

    3. The attempt at a solution

    F(friction) = [itex]\mu[/itex] * mg(y)

    F[itex]\rightarrow[/itex] = F(f) + F(mg(x))

    a=F[itex]\div[/itex]M[itex]\rightarrow[/itex]F[itex]\div[/itex]m=232,7[itex]\div[/itex]69 = 3,34m/s^2

    s = (v^2 - v(o)^2) / 2a = 11,8m

    sin(20)*11,8=4,05...[itex]\approx[/itex] 4,1m

    the answer should be 4,0m. What am I doing wrong?
  2. jcsd
  3. Dec 18, 2013 #2


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    Gold Member

    Physics looks good, maths is off.....redo the math: you should get something like 4,02 which rounded to two sig figs is 4,0
  4. Dec 18, 2013 #3
    I see, thanks. I thought my problem was that I was thinking about it all wrong. I redid the math and it checks out.

    Appreciate the help!
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