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Homework Help: A car kinematics problem

  1. Feb 19, 2007 #1
    Suppose a car travelling at 12.0m/s sees a traffic light turn red. After 0.510s have elapsed, the driver applies the brakes, and the car decelerates at 6.20m/s^2. What is the stopping distance of the car, as measured from the point where the driver first notices the red light?


    2. Relevant equations

    d=vt
    vf^2=vi^2+2ad



    3. The attempt at a solution

    d before breaking
    d=vt
    =12(0.51)
    d=6.12m

    d after breaking

    vf^2=vi^2+2ad
    0^2=12^2+2(-6.20)d
    -144=2(-6.20)d
    d=11.6m
     
  2. jcsd
  3. Feb 19, 2007 #2
    seems like you got it right.
     
  4. Feb 19, 2007 #3
    looks right to me
     
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