Answer:
the work done by friction is 12 J.
Step-by-step explanation:
Given;
mass of the car, m = 2 kg
initial speed of the car, u = 4 m/s
final speed of the car, v = 2 m/s
The work done by friction is equal to change in kinetic energy of the car,
W = ΔK.E
W = ¹/₂m(v² - u²)
W = ¹/₂ x 2 (2² - 4²)
W = -12 J (the negative sign indicates that it is a wasted energy)
Therefore, the work done by friction is 12 J.