When we move a body over another body, a force acts in a direction opposite to the motion is known as friction or force of friction. This opposite force acts due to irregularities on the surface of two bodies.

The friction can be of the following types.

1.       Static friction: It is the friction experienced by the body when it tends to move.

2.       Sliding friction: It is experienced when a body slides over another body.

3.       Rolling friction: It is experienced when a body rolls over another body.