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Homework Help: Train Physics Problem

  1. Feb 6, 2010 #1
    1. The problem statement, all variables and given/known data

    A given train can stop in t seconds when it is running at its maximum speed. The train driver sees a car stalled at an intersection that is d1 meters ahead of the train, and instantly pulls the brake starting while at its maximum speed. The train reaches the intersection u seconds later, but does not hit the car because the car darts out of the way at the last moment. The train travels d2 more meters before it comes to a complete stop.

    Supposing that the train's acceleration through all this is constant, how far was the train from the car? In other words, what is d1? (in terms of t, u and d2)

    2. Relevant equations

    v=v0 + at
    vav= (1/2)(v0+v)

    3. The attempt at a solution

    I have a bunch of equations and I can't seem to put them together to find the solution.
  2. jcsd
  3. Feb 7, 2010 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Think in terms of a, Δv, and Δt, and see if you can set up some equations.
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