# Types of friction?

May 31, 2018

See Explanation

#### Explanation:

There are 2 types of friction:

1. Static friction

• Given by $F = {\mu}_{s} N$, where N is the normal reaction force.
• The value of friction when there is an applied force but the object has not yet moved .

2. Kinetic friction

• Given by $F = {\mu}_{k} N$, where N is the normal reaction force.
• The value of friction when there is an applied force and the object is moving.

When an object just starts to moves, it encounters the greatest friction (i.e. coefficient of static friction) but once the object starts moving, it is actually easier to move already (i.e. coefficient of kinetic friction < coefficient of static friction).