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 is equal to the frictional force times the distance over which it acts. The frictional force is the product of the coefficient of friction and the normal force, which is equal to the weight of the car (mass times gravity). Therefore, the most massive car (car L) will have the greatest frictional force and thus the greatest work done by friction.

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