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Making the Light Final Exam Review

  1. Dec 13, 2008 #1
    1. The problem statement, all variables and given/known data
    Making the light. While traveling in your car at a constant 12 m/s, you notice a traffic light 44 m in front of
    you turn yellow. You know that the light will turn red in 3.0 seconds, and that you can speed up at a rate of 6.0
    m/s/s. You’re also aware that it takes you 1.0 second to actually step on the gas and begin speeding up at that
    rate. Will you make it through the light before it turns red?

    2. Relevant equations
    xf=xi+Vi(delta T)+(.5)a(Delta T)^2

    3. The attempt at a solution

    In the one second delay because of reaction time the car travels 12 meters corresponding to the 12m/s velocity so xi=12m

    xf=12m + (12m/s)(2s) + (.5)(6m/s/s)(2^2)

    36m<44m to the light so the car will not make the light!
  2. jcsd
  3. Dec 13, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Redo that calculation.
  4. Dec 13, 2008 #3
    Ah math error kills thank you.

    48m>44m car will make the light!
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