Lesson 12-1:
Gravity and Friction
Types of Forces
Gravity
Friction
. . . .

Kinds of Friction

Rolling Friction
Friction may also be rolling friction, or the force between a wheel or roller and the surface which it is in contact with. Some examples of situations that illustrate rolling friction include the wheels of a car moving on the road, the bowling balls rolling on the alley, and the wheels of the skateboard played by the young boys in a park.