Question

A motor car is moving with a velocity of 108 km/ h and it takes 4 sec to stop after the brakes one applied. Calculate the force exerted by the brakes on the motor car if its mass along with the passengers is 1000 kg.

Answer 1

We are given that

Initial velocity of motor car = 108 km/h

⇒ (u) = \(\frac{108\times 1000}{60\times 60}\) = 30 m/s

Final velocity (v) = 0 m/s

Total mass of the motor car along with its passengers (m) = 1000 kg.

Time is taken to stop the motor car (t) = 4 sec.

The negative sign shows that the force exerted by the brakes is opposite to the direction of motion of the motor car.