Kinds of Friction

Static Friction
When the two objects in contact are not moving, the friction between them is said to be static. A pencil lying on your table, the books on a shelf, and a bag resting on a chair possess static friction. There are two surfaces rubbing each other in each situation—the pencil and the table, the books and the shelf, and the bag and the chair—and there is static friction between these pairs of objects. The objects remain at rest because of the balanced forces they exert toward each other.

You can also experience sliding friction when you play on a slide in the playground and when you go through the slides in swimming pools.

Sliding Friction
Another type of friction is the sliding friction, or the type of friction that occurs when the bumps and hollows on the surfaces of two materials resist against each other. There is sliding friction when two solid surfaces slide over each other. Sliding friction is produced in instances such as pushing and pulling the mouse of your computer and pushing a flatiron on the cloth during ironing.

You can also experience sliding friction when you play on a slide in the playground and when you go through the slides in swimming pools.