Acar of mass 900 kg is traveling at 20 m/s when the brakes are applied. the car then comes to a complete stop in 5 s. what is the average power that the brakes produce in stopping the car?

a. 36,000 w
b. 7200 w
c. 3600 w
d. 1800 w

A. 36,000 W

Explanation:

= mass of the car = 900 kg

= Initial speed of the car = 20 m/s

= Final speed of the car = 0 m/s

= Work done by the brakes on the car

Magnitude of work done on the car by the brakes is same as the change in kinetic energy of the car.hence

= time taken by the car to come to stop = 5 s

= Average power produced by the car

Average power produced by the car is given as

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