Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes. The most massive car is car L, and the least massive is car N. If the tires of all three cars have identical
Coefficients of kinetic friction with the road surface, for which car is the amount of work done by
Friction in stopping it the greatest?

Question

Quizplus · Accepted Answer

The work done by friction to stop a car is equal to the change in kinetic energy of the car. Since kinetic energy is given by $ \frac{1}{2}mv^2 $, where $ m $ is mass and $ v $ is velocity, a more massive car (car L, in this case) will have more kinetic energy for the same speed. Therefore, more work will be required to stop car L compared to the others.

Three Cars (Car L, Car M, and Car N) Are