Answer:
240000 Joules
Step-by-step explanation:
Applying,
The work that must be done by the frictional force of the brake to stop the car must be equal to the kinetic energy of the car.
W = mv²/2.................. Equation 1
Where W = work done by the frictional force of the brake, m = mass of the car, v = velocity of the car.
From the question,
Given: m = 1200 kg, v = 20 m/s
Substitute these values into equation 1
W = (1200×20²)/2
W = 240000 Joules