Question

A 2500 kg car is moving at 20 m/s when brakes are applied. If the average force exerted by the brakes
is 5000 N, find the distance travelled by the car before it comes to rest?

Answer 1

Acceleration due to friction (retardation) (a) = - μg=−0.9×10=−9m/s2

Final velocity, v=0m/s

Initial velocity, u=20m/s

Applying formula: v2=u2+2as

Where s is the distance traveled by car before it come to rest.

⇒02=202+2(−9)s

⇒18s=400

⇒s=22.2 m