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Homework Help: Roller coaster work gravitational energy.

  1. Nov 12, 2011 #1
    1. The problem statement, all variables and given/known data
    a frictionless roller coaster car of mass m = 954 kg tops the first hill with speed v0 = 24.2 m/s at height h = 30.8 m. How much work does the gravitational force do on the car from that point to (a) point A. (same height)

    2. Relevant equations

    3. The attempt at a solution
    One question is baffling me, do I need to include kinetic energy when calculating using the change of gravitational potential energy? Does it mean that question (a), work does by the gravitational force is zero ?
  2. jcsd
  3. Nov 12, 2011 #2

    Doc Al

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    Staff: Mentor

    That's what I would say. Going from one point to another of equal height, the change in gravitational PE (and thus the work done by gravity) is zero.
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