What kinds of friction do you know?

There are three kinds of friction:

1. Static friction: It is a force acting on the surface which keeps the object at rest when acted upon by an external force which tends to move the object across the floor.

Example: Holding a wooden block against a wall by applying force perpendicular to the wall. Here the block stays at rest until a perpendicular force acts on the block and is set into motion once the force is removed. While the block is at rest, the friction acting is known as static friction.

2. Sliding friction: Once the object is set in motion, it experiences sliding friction.

Example: A block being slid across a slant surface experiences sliding friction.

3. Rolling friction: It is a type of frictional force resisting the motion when a body rolls on a surface.

Example: The friction between car wheel and the road is called rolling friction and it is responsible for halt of the car when the tyres of the car are not driven by the engine.