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Determine the stopping distances for a car with an initial speed of 87 km/h and human reaction time of 2.0 s for the following accelerations.

(a) a = -4.0 m/s2
(b) a = -8.0 m/s2

1 answer

Vo = 87km/h = 87,000m/3600s = 24.2 m/s. = Initial velocity.

a. d1 = 24.2 * 2 =
V^2 = Vo^2 + 2a*d2.
V = 0, Vo = 24.2 m/s, a = -4.0 m/s^2, d2 = ?.
d1+d2 = Stopping distance.

b. V^2 = Vo^2 + 2a*d2.
V = 0, Vo = 24.2 m/s^2, a = -8.0 m/s^2, d2 = ?.
d1+d2 = stopping distance.