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Homework Help: 1D kinematics

  1. Jun 18, 2012 #1
    A car starts from rest and travels for 6.0 s with a uniform acceleration of +2.7 m/s2. The driver then applies the brakes, causing a uniform acceleration of −1.0 m/s2. If the brakes are applied for 1.0 s, determine each of the following.

    (a) How fast is the car going at the end of the braking period?

    (b) How far has the car gone?

    So, I already found out part a which is 15.2m/s by utilizing the equation v=v(initial)+at. I'm having some trouble finding the distance traveled with two different accelerations.
  2. jcsd
  3. Jun 18, 2012 #2
    As you probably did with the speed, break the problem down into two part: the acceleration phase and the deceleration phase. Use the distance and speed at the end of the first phase as the starting point for the second phase (ie, treat it like a second problem: "a car at x m from the origin, traveling at v m/s brakes at 1 m/s^s for 1s; find its speed and position after it has finished braking").
  4. Jun 18, 2012 #3
    ok thanks!
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