What does friction do?

Friction is a force that tends to stop motion or resist the motion of objects. Friction is always a negative force, which means it acts in a direction opposite to the direction of the force applied to the object. Movement of objects through air and liquids gives rise to friction.

Although friction is not always desirable, it does have a role to play in our lives. Walking would be impossible without friction. The friction between the wheels of a car and the road make it possible to drive a car. Writing on paper with a pen is also possible due to friction.

Types of friction include static, rolling and kinetic friction.