0Key points:
- Friction does not oppose the motion, but it opposes relative movement between the contact surfaces.
- When there is no relative motion between the contact surfaces, then no friction force will act. Still, if there is no relative motion between the contact surfaces, but there is a tendency to be in relative motion, static friction will work.
- Static friction is self-adjusting in nature.
- Static friction has a maximum limit, and that maximum friction is called as limiting friction.
- When there is relative motion between the contact surfaces, then kinetic or dynamic friction will act.
- Kinetic friction is constant in magnitude.
