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Math Help - Help with problem

  1. #1
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    Help with problem

    1.) A skier coasts down a very smooth, 10-m-high. If the speed of the skier on the top of the slope is 5.0 m/s, what is his speed at the bottom of the slope?
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  2. #2
    Senior Member tukeywilliams's Avatar
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    Use  U_1 + K_1 + W_{\text{other}} = U_2 + K_2 (conservation of energy)

    Or use kinematic equations (under the assumption that we have constant acceleration). It would probably be better to use energy methods.

     v_f = v_0 + at

     x-x_0 = \frac{1}{2}(v_0 + v_f)t

     x-x_0 = v_{x0}t + \frac{1}{2}at^2

     v_{f}^2 = v_{0}^2 + 2a(x-x_0)
    Last edited by tukeywilliams; August 1st 2007 at 07:17 PM.
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  3. #3
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by tukeywilliams View Post
    Use  U_1 + K_1 + W_{\text{other}} = U_2 + K_2 (conservation of energy)

    Or use kinematic equations

     v_f = v_0 + at

     x-x_0 = \frac{1}{2}(v_0 + v_f)t

     x-x_0 = v_{x0}t + \frac{1}{2}at^2

     v_{f}^2 = v_{0}^2 + 2a(x-x_0)
    The use of the kinematic equations depends on the object having a constant acceleration. Since we aren't given any information about what the slope is like. (Yes, I know "slopes" are typically represented by lines, but I don't feel we can make that assumption in this case. We also don't have any information about the grade of the slope. As it happens the answer doesn't depend on these details, but that is a consequence of the energy theorem.)

    To make a long story short, use energy methods.

    -Dan
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