Static friction is a force that keeps an object at rest and resists the movement of one solid object over another. It is the frictional force between the surfaces of two substances when they are not in motion with respect to each other. Static friction is what keeps a stationary object from moving when a force is applied to it. The force of static friction is self-regulating, meaning it is precisely balanced by the applied force for the duration of the stationary state of the body. Static friction is classified as a type of dry friction. Some examples of static friction include papers on a tabletop, a towel hanging on a rack, a bookmark in a book, and a car parked on a hill. The coefficient of static friction is generally found to be greater than the coefficient of kinetic friction.