Two cars that have the same mass are moving around a circular track at the same constant speed. The track is perfectly level. If car 1 is at the inner edge of the track and car 2 is at the outer edge, then
A) the frictional force on car 1 is greater than the frictional force on car 2.
B) the frictional force on car 1 is less than the frictional force on car 2.
C) the frictional forces on both cars are equal and greater than zero.
D) the frictional force on both cars is zero.

Question

Quizplus · Accepted Answer

The frictional force, which provides the centripetal force necessary for circular motion, depends on the radius of the circle. Since car 1 is on the inner edge, it travels a smaller circle with a smaller radius, requiring less frictional force than car 2, which travels on a larger circle with a larger radius.

Two Cars That Have the Same Mass Are Moving Around