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Homework Help: Find time given velocity and distance

  1. Feb 5, 2010 #1
    1. The problem statement, all variables and given/known data

    A certain vehicle requires a distance of 29 m to stop when it is traveling at 28 m/s.
    (a) What magnitude of acceleration is produced by braking under these conditions?
    (b) If a jaywalker is 27 m in front of the vehicle when the driver first applies the brakes, how much time does the pedestrian have to get out of the way?

    2. Relevant equations

    v=vo + at
    x - xo = vot + [tex]\frac{1}{2}[/tex]at2
    v2 = vo2 + 2a(x - xo)

    are the given equations for what we're learning.

    3. The attempt at a solution

    (a) 13.52m/s2
    (b) is what I cannot find
     
  2. jcsd
  3. Feb 5, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    I'll rephrase the question: How long does it take the vehicle to cover 27 m?
     
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