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Gre4nikov [31]
3 years ago
10

An inattentive driver is traveling 18.0 m/s when he notices a red light ahead. his car is capable of decelerating at a rate of 3

.35 m/s2 . if it takes him 0.200 s to get the brakes on and he is 20.0 m from the intersection when he sees the light, will he be able to stop in time?
Physics
1 answer:
ryzh [129]3 years ago
3 0

Speed of the car given initially

v = 18 m/s

deceleration of the car after applying brakes will be

a = 3.35 m/s^2

Reaction time of the driver = 0.200 s

Now when he see the red light distance covered by the till he start pressing the brakes

d_1 = v* t

d_1 = 18* 0.200 = 3.6 m

Now after applying brakes the distance covered by the car before it stops is given by kinematics equation

v_f^2 - v_i^2 = 2 a s

here

vi = 18 m/s

vf = 0

a = - 3.35

so now we will have

0^2 - 18^2 = 2*(-3.35)(s)

s = 48.35 m

So total distance after which car will stop is

d = d_1 + d_2

d = 48.35 + 3.6 = 51.95 m

So car will not stop before the intersection as it is at distance 20 m

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Answer:

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