1. Friction Honors Physics

2. What we know.. 1.It’s a force! 2.It opposes motion 3.It requires contact 4.It is somehow related to the normal force..

3. How does it work? Click me! 

4. What does friction actually depend on? The normal force Describes the amount of contact The “coefficient of friction” Describes the type of contact Different types exist Denoted by the Greek letter “µ”

5. What do you see?

6. F FR is dependent upon surface texture

7. Types of Friction: Static Object is at rest v = 0m/s Denoted by µ s Unitless Always > µ k Produces a variable “static friction” force It is most useful when studying the maximum amount of friction possible before motion occurs

8. Types of Friction: Kinetic Object is in motion v ≠ 0m/s Denoted by µ k Unitless Always < µ s Produces a constant “kinetic friction” force.

9. Threshold of static friction Kinetic friction

10. Given: m = 100kg µ s = 0.45 µ k = 0.35 Find: F FR,s max = ? F FR,k = ? Threshold of static friction Kinetic friction

11. Go Skate.. For Science!