In the design of a new roller coaster, engineers must consider the coefficient of friction between the coaster wheels and the tracks. If the coefficient of static friction is 0.6 and the total weight of the roller coaster is 5000 N, what is the maximum force of static friction that can be exerted before the coaster starts to slide?

The maximum static friction force is found by multiplying the coefficient of static friction by the normal force. The normal force here is just the coaster’s weight, 5000 N, because the track is horizontal. So we calculate 0. 6 × 5000 N, which equals 3000 N. This means the wheels can resist up to 3000 N of sliding before the coaster starts to move.