The laws of kinetic friction are,
- The force of kinetic friction always acts in the opposite direction to which body is moving.
- The force of kinetic friction remains constant for moderate speed but it decreases with an increase in speed.
- Magnitude of kinetic friction has a constant ratio to normal reaction between two surface. The ratio of kinetic friction is slightly less than that in case of limiting force of static friction.
- The coefficient of kinetic friction is independent of the area and shape of the contacting surfaces.
The formula for law of kinetic friction is given as,
FK = µk N ——— where FK =Force of kinetic friction, µk= coefficient of kinetic friction and N=Normal force
The formula for coefficient of kinetic friction is given as,
µk = FK / N