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Homework Help: Collision of cars - time

  1. Jan 13, 2010 #1
    1. You are arguing over a cell phone while trailing an unmarked police car by 34 m. Both your car and the police car are traveling at 105 km/h. Your argument diverts your attention from the police car for 2.0 s (long enough for you to look at the phone and yell, "I won't do that!"). At the beginning of that 2.0 s, the police officer begins emergency braking at 5 m/s2.
    (a) What is the separation between the two cars when your attention finally returns? (Hint: This problem might be a bit easier to solve using the idea of relative velocity.)
    (b) Suppose it takes you another 0.4 s to realize your danger and begin braking. If you too brake at 5 m/s2, what is your speed when you hit the police car?
    How much time passes between your initial braking and the collision?
    How much distance do you cover during this time (i.e., while braking)?
  2. jcsd
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