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Homework Help: Work problem with friction

  1. Oct 1, 2007 #1
    1. The problem statement, all variables and given/known data
    A small block slides along a track from one level to a higher level, by moving through an intermediate valley (see Figure). The track is frictionless until the block reaches the higher level. There a frictional force stops the block in a distance d. Assume that the block's initial speed is 10 m/s, the height difference h is 1.0 m, and μk is 0.32. Find the distance d that the block travels on the higher level before stopping.


    2. Relevant equations

    non conservative work = (KE final - KE initial) + (PE final - PE initial)

    3. The attempt at a solution

    I think think the part o that's really giving me trouble is the valley. I realize that once the block reaches the other side with the friction it's all forces and kinematics, but how that tie in with the work part? I'm just really confused on how to approach this problem.
    Last edited: Oct 1, 2007
  2. jcsd
  3. Oct 1, 2007 #2

    Chi Meson

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    The valley does not matter since it is frictionless. All that matters is the kinetic energy just before it hits the friction. It is exactly the same as if the block simple rose 1 m up a frictionless ramp.

    Then, what is the force that does the (negative) work to stop the block (to take away its kinetic energy)?

    How is work calculated?
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