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Homework Help: Train acceleration! Please help!

  1. Sep 20, 2007 #1
    1. The problem statement, all variables and given/known data
    A train is moving parallel and adjacent to a highway with a constant speed of 33 m/s. Initially a car is 32 m behind the train, traveling in the same direction as the train at 47 m/s and accelerating at 4 m/s^2.
    What is the speed of the car just as it passes the train? Answer in units of m/s.

    2. Relevant equations
    So far, I have thought of using delta x= Vot+ 1/2at^2
    I also think that I have to account for the displacement between the two trains, which is 14 m.
    The thing that I don't understand is how to calculate something as it passes or catches up to another thing.

    If there is any advice, thanks!
  2. jcsd
  3. Sep 20, 2007 #2


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    Homework Helper

    Get the two equations for displacement/position in terms of time...

    to find when they meet, set the two displacements equal... then you can get the velocity of the car at this time...

    The main part is getting the two initial equations right...
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