Friction is a force that resists the motion of objects past each other . The force of friction is directly proportional to the coefficient of friction, mu 1 , and the normal force. F f = mu F n There are two main types of friction: static (stationary) and kinetic (sliding). Static friction is a force that prevents objects from sliding past each other. Kinetic friction is a force that slows down objects that are already sliding past each other.
