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Homework Help: Dealing with Velocity and acceleration. What do I do next? =P

  1. Sep 5, 2008 #1
    1. The problem statement, all variables and given/known data

    David is driving a steady 21.0 m/s when he passes Tina, who is sitting in her car at rest. Tina begins to accelerate at a steady 2.70 m/s^2 at the instant when David passes.

    V= 21m/s

    V_i= 0 m/s
    V_f= ?
    acc= 2.7 m/s^2

    How far does Tina drive before passing David?
    What is her speed as she passes him?

    2. Relevant equations

    D_f= D_i + V_i + t_f + (1/2)at_f^2
    V_f^2= V_i^2 + 2a(D_f - D_i)
    V_f= V_i +at

    3. The attempt at a solution

    Well, I realy dont have an attempt because I have no clue what to do. Any suggestions
  2. jcsd
  3. Sep 5, 2008 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    At the point Tina catches David their distances should be the same. You can set the two equations of motion equal and then solve for time. Once you have time you can solve for the other things.
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