2.  Spend 15-20 minutes completing the activity regarding friction.

3.  Support force against weight of an object  If more force is applied in the same direction as gravity (and the surface doesn’t break), the surface will provide more normal force to balance the net force.

4.  What is the normal force? ◦ Angle = 30° ◦ W = 100 ◦ F = 10

5.  Static Friction ◦ Friction between the surface and an object at rest  Kinetic Friction ◦ Friction between the surface and a moving object

6.  Strength of the maximum friction depends on… ◦ The “roughness” of the two materials (  ) ◦ Normal force supporting the object (How closely pressed the two objects are) (F N )  f k = kinetic friction force,  = coefficient of friction, F N = Normal Force

7.  The maximum static friction is the maximum limit of friction force the two objects can have before moving.