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Homework Help: 1D Dynamics Problem

  1. Sep 23, 2012 #1
    1D Dynamics Problem!!!

    1. The problem statement, all variables and given/known data
    A car of mass 1100kg is traveling at a constant velocity of 60 km/hr, east. The coefficient of friction between the tires and the road is 0.45.
    The driver of the car sees the traffic light in front turning red and steps on the brake, only to find that the brakes are not working. If the car is 35m before the intersection when this happens, would it be able to come to a stop before entering the intersection?

    2. Relevant equations
    F = ma
    d = vt + 1/2at^2
    vf^2 = vi^2 + 2ad
    vf = vi + at

    3. The attempt at a solution

    I've fiddled around with the bottom three kinematic equations, but I don't seem to be getting anywhere..
  2. jcsd
  3. Sep 23, 2012 #2


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    Science Advisor
    Homework Helper

    Re: 1D Dynamics Problem!!!

    It looks like you are supposed to assume the car is slowing down because of the 0.45 kinetic friction value. Start by trying to compute the acceleration a. To do that try to find the frictional force on the car first.
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