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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.)
    m
    (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?
    km/h
    How much time passes between your initial braking and the collision?
    s
    How much distance do you cover during this time (i.e., while braking)?
     
  2. jcsd
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