1. FRICTION

2. FRICTION A force that resists motion (or tendency to move) between two objects in contact

3. The materials in contact The normal force
Depends on 2 factors
The materials in contact
The normal force

4. Draw in the friction vector.Ff

5. Scroll down to find static friction animation.
Simulation
Scroll down to find static friction animation.

6. Static friction force A force is applied but the object doesn’t move
No motion = net force = 0
The friction force is in the opposite direction of the applied force
Size of friction _______ the applied force

7. Static Friction FN Ff FA FW
Net Force = Zero

8. Kinetic friction force
Kinetic means : force is applied and the object moves but friction slows it down
The friction force is in opposite direction to the motion
The friction force is smaller than the applied force

9. Kinetic Friction AcceleratingFN Ff FA FW
Net Force ≠ Zero

10. Kinetic Friction Constant VelocityFN Ff FA FW
Net Force = Zero

11. on a horizontal surface
Friction equation
Ff = μ FN
FN =FW
on a horizontal surface

12. Coefficients of Friction
μs = coefficient of static friction μk = coefficient of kinetic friction

13. Air Resistance
When an object moves through air it runs into air molecules.
It is a type of friction because it resists the motion of the object.

14. A special situation Terminal velocity is when
The object stops accelerating and travels at constant velocity.
FAir = FW and Fnet = 0

15. A special situation FA FW

16. Terminal Velocity https://www.youtube.com/watch?v=p0IZsfzDS4s
Scroll down even more

17. Classwork/Homework
Static Friction Problems