Friction is the force that occurs when two different surfaces come into contact and move
past one another. Friction generates heat and sound and in many situations has a very useful
application, e.g. the brakes of a car.
Friction is the force which opposes the motion of one object past another.
Friction can be reduced when:
• Air is used to act as a cushion, e.g. a hovercraft
• Aerodynamic streamlined shapes, e.g. a plane.
Without friction there would be chaos as nothing would stay in place.