Question

what is friction ? and it's different types?

Answer 1

Friction is the force that opposes the motion of an object
There are different types of friction. A book moving across the desk is an example of sliding friction. As the book slides cross the desk, the bottom of the book is touching the desk. The source of the friction is the contact between the surface of the book and the desk. The weight of the object and the type of surface it moves over determine the amount of sliding friction present between the two objects. A heavy object exerts more pressure on the surface it slides over, so the sliding friction will be greater.

Air, water and oil are all fluids. Air resistance is a type of fluid friction. As an object falls, air resistance pushes up on the object.

When you ride a bicycle, the contact between the wheel and the road is an example of rolling friction. When an object rolls over a surface, the force needed to overcome rolling friction is much less than that needed to overcome sliding friction

Answer 2

Friction is the force that opposes motion between any surfaces that are in contact.
There are four types of friction:static,sliding,rolling and fluid friction