The brakes of a car are applied, causing it to slow down at a rate of 10 ft/s2. Knowing that the car stops in 300 ft, determine (a) how fast the car was traveling immediately before the brakes were applied,
(b) the time required for the car to stop.

(a) The velocity of the car before the brakes were applied is 77.46 ft/s

(b) The time required for the car to stop is 7.8 s

Explanation:

Given;

acceleration of the car, a = 10 ft/s²

distance traveled by the car, d = 300 ft

(a) the velocity of the car before the brakes were applied is given;

v² = u² + 2ad

v² = 0 + 2(10 x 300)

v² = 6000

v = √6000

v = 77.46 ft/s

(b) the time required for the car to stop

d = ut + ¹/₂at²

d = 0 +  ¹/₂at²

d = ¹/₂at²

t² = 2d / a

t = √ ( 2d / a)

t = √ ( 2 x 300 / 10)

t = 7.8 s

Therefore, the time required for the car to stop is 7.8 s