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Homework Help: Another motion problem for constant acceleration

  1. Sep 19, 2010 #1
    1. The problem statement, all variables and given/known data
    A truck travels at a constant speed of 28.0 m/s in the fast lane of a two-lane highway. It approaches a stationary car stopped a the side of the road. When the truck is still 125 m behind the car, the car pulls out into the slow lane with an acceleration of 2.6 m/s2. How long will it take the truck to reach the car? (Answer is 6.32 s)


    2. Relevant equations
    N / A


    3. The attempt at a solution
    I have no idea how to do this :(
     
  2. jcsd
  3. Sep 19, 2010 #2

    Doc Al

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    Staff: Mentor

    This is similar to the wolf/rabbit problem.

    Write the position as a function of time for both the truck and the car. Measure from the initial position of the truck when the car starts moving. Set them equal.
     
  4. Sep 19, 2010 #3
    I'm sorry, but could you please write that out in equation form? I am not a clever man.
     
  5. Sep 19, 2010 #4

    Doc Al

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    Staff: Mentor

    Oh, you're clever enough. :smile:

    You just solved an almost identical problem! Hint: The truck moves at constant speed; the car accelerates.
     
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