Question

A 1800 Kg car is moving at 30m/s. when brakes are applied. If the average force exerted by the brakes is 6000N, find the distance travelled by the car before it comes to rest. Also find the work done by frictional force to stop it.

Answer 1

Answer:

Mass m  = 1800 kg

Initial velocity u = 30 m/s

F = 6000 N = ma = 1800 a

a = 6000/1800 = 3.33 m/s2.

Retardation = - a

Final velocity v = 0 m/s

v2 - u2 = 2aS

Distance travelled S = (0 - 302)/(-2 x 3.33)

                                   = 900/6.66

                                   =135.1 m

Explanation: