Question

4. A 1,800 kg car is traveling at 40 m/s when the driver slams in the brakes to stop the car. The brakes apply a maximum force of 24,600 N. How far will

the car travel while coming to a stop?
O 117 meters
0 58.5 meters
O 29.3 meters

Answer 1

The brakes do

W = ∆K = 0 - 1/2 (1800 kg) (40 m/s)² = -1.44 MJ (megaJoules)

of work on the car to stop it. They apply a negative force since the braking opposes the car's forward displacement, so the car stops over a distance x such that

W = (-24.6 kN) x ==> x ≈ 58.5 m