Problem 2.45 You\'re driving down the highway late one night at 20 m/s when a de
ID: 1407883 • Letter: P
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Problem 2.45 You're driving down the highway late one night at 20 m/s when a deer steps onto the road 52 m in front of you. Your reaction time before stepping on the brakes is 0.50 s, and the maximum deceleration of your car is 10 in/s^2. Part A How much distance is between you and the deer when you come to a stop? Express your answer to two significant figures and include the appropriate units. Part B What is the maximum speed you could have and still not hit the deer? Express your answer to two significant figures and include the appropriate units.Explanation / Answer
initial velocity = vo = 20 m/s
distance to be travelled before brakes applied = x = 52 m
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distance travelled inreaction time = x1 = 0.5*20 = 10 m
distance to be travelled x2 = 52-10 = 42
final spped = vf = 0
from equations of motion
vf^2 - vo^2 = 2*a*x2
0^2 - 20^2 = -2*10*x2
x2 = 20
distance between the deer and car = 42-20 = 22 m <<<-answer
++++++++++++++
distance to be travelled = 52 m
vf = 0
initial velocity = Vmax = v
distance teravelled in reaction time = x1 = v*0.5
distance between the deer and car before coming to rest x2 = 52-0.5*v
vf^2 - v^2 = 2*a*x2
0 - v^2 = -2*10*(52-0.5v)
v = 28 m/s <<<-answer
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