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Homework Help: Driving towards a deer; Constant

  1. Jan 31, 2013 #1
    1. The problem statement, all variables and given/known data
    driving down K10 highway (70 mph speed limit, this info is not given) one night a deer jumps out in front of you at a distance of 100 m. You don't notice for 1.5 s. As you are skidding towards the deer your acceleration is -5 m/s. What is the max initial speed you could have had to avoid hitting the deer?

    2. Relevant equations Constant motion equations

    3. The attempt at a solution
    70 mph = 31.2861 m/s

    1.5 * 31.2861 = 46.9292 meters traveled b/w deer jumping in front of car and when I hit the brakes.

    100-46.9292 = 53.0708 Meters to slow to a velocity of 0

    a= -5 m/s2.

    V0 = 31.2861 m/s

    Δx = 0 - 53.0708 = -53.0708 m

    vf= 0

    So what max speed will allow my vf→0 over -53.0708 meters at an acceleration of -5 m/s. I have only calculated numbers greater than my v0
  2. jcsd
  3. Jan 31, 2013 #2
    never mind I got it. Thanks anyway
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