- The frictional force between two stationary surfaces is called the static friction, fs.
- The frictional force between two sliding surfaces is called the kinetic friction, fk.
- It can be shown empirically that between two particular surfaces
- static friction fs ranges from zero to a maximum value.
0 < fs < μsN
- kinetic friction fk is constant and independent of speed.
fk = μkN
- maximum static friction is larger than kinetic friction.