During emergency braking, a car moving at a speed of 36 km / h stopped in 4 seconds.

During emergency braking, a car moving at a speed of 36 km / h stopped in 4 seconds. Determine vehicle acceleration and braking distance.

V0 = 36 km / h = 36 * 1000m / 3600 s = 10 m / s
t = 4 s
V = 0 – after 4 seconds the car stopped
a -?
S -?
acceleration formula:
a = (V-V0) / t
a = (0 – 10) / 4 = – 2.5 m / s ^ 2
S = V0 * t + a * t ^ 2/2
S = 10 * 4 – 2.5 * 4 ^ 2/2 = 40 -20 = 20 m
Answer: car acceleration a = 2.5 m / s ^ 2; braking distance S = 20 m