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Homework Help: Please check if I did it right?

  1. Feb 24, 2008 #1
    1. The problem statement, all variables and given/known data
    A skier starts from rest at the top of a 26 degree slope 1.3Km long.
    how long does it take to reach the bottom? (no friction)





    The attempt at a solution
    m=mass
    m*g*sin(24) = ma(at slope direction)
    divide both side by m
    we got
    g*sin(24)=a

    then use
    v^2(final) = V^2(initial)+2(9.8m/s^2)(sin(24))(1300m)
    V^2(final) = 0+2(9.8m/s^2)(sin(24))(1300m) we know that initial v is zero.
    we get V from the equation above.
    then use
    v= v(initial)+at
    v=0+(9.8m/s^2)sin(24)t
    t=V/9.8sin(24).
    done!
     
  2. jcsd
  3. Feb 24, 2008 #2
    I suppose it would be okay, but why not just use

    [tex]s(t) = s_0 + v_0t +\frac{1}{2}at^2[/tex]

    and solve for t?

    Did you mean a 24 degree slope, or are you putting in the wrong angle?
     
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