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Homework Help: Kinematic problem help

  1. Sep 18, 2007 #1
    Kinematic problem help!!!!

    1. The problem statement, all variables and given/known data

    David is driving a steady 31.0 m/s when he passes Tina, who is sitting in her car at rest. Tina begins to accelerate at a steady 2.80 m/s^2 at the instant when David passes.

    How far does Tina drive before passing David?

    What is her speed as she passes him?

    2. Relevant equations

    3. The attempt at a solution

    I know that there is two different cars moving seperatly and they will need two different equations, but im not sure exactly how to go about this one?
  2. jcsd
  3. Sep 18, 2007 #2


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    For the steady car s=vt, for the accelarating one s=ut+1/2at^2
  4. Sep 18, 2007 #3
    OK im just not sure what do with the equations, and what is s representing in these equations?
  5. Sep 18, 2007 #4
    's' is the standard abbreviation for displacement.

    If you are finding it hard to use the equations directly it's probably because you don't quite know what you're heading for. This may help, or it my not, if both car's movement were mapped onto a distance-time graph would they cross? If so, what does this mean in respect to the equations.

    ~ Ek.
  6. Sep 18, 2007 #5
    What does u represent in these equations and i am having trouble finding time, what steps do I need to find this?
  7. Sep 18, 2007 #6


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    There is a sticky describing the equations ( with better latex formatting).
    s = distance
    t = time
    a = acceleration
    u = initial velocity
    v = final velocity
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