Where does friction occur? Can it happen in liquids, air, with solids?

Sagot :

friction can happen with solids it is when two things are rubbed together and they make heat.
Friction is the contact force.  When there is  relative motion between two surfaces in contact, there is the force of friction acting on them.
Surface of object 1  opposes the relative motion of object2 and vice verse.  These two forces are equal and in opposite in direction.

It happens between solid and solid surfaces.

This type of opposing force in fluids or gas is called DRAG.  When a ball is falling from a height on to the ground, there is an opposing force - called drag.