Friction is the force between an object in motion and the surface on which it moves. Friction is the external force that acts on objects and causes them to slow down when no other external force acts upon them. Inertia is the tendency of a body in motion to remain in motion.
Friction is the drive between an object in motion and the surface on which it moves. Friction is the outside constrain that acts on objects and causes them to moderate down when no other outside drive acts upon them.
