Question

A 2 kg RC car is driving at a speed of 4 m/s. The brakes are hit from the controller and the car slows down to a speed of 2 m/s. What is the work done by friction? *

Answer 1

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.