1. F f = . F norm Friction “  ” is the coefficient of friction…it represents the types of surfaces that are in contact with each other

2. F f = . F norm Friction  is a large value for rough surfaces (0.7 is a high  )  is a small value for smooth surfaces (0.3 is a low  )

3. F f = . F norm Friction The coefficient of friction has two classifications: 1. Static – means stationary 2. Kinetic – means sliding

4. F f = . F norm Friction It takes a greater amount of force to start an object into motion than it does to keep it in motion.

5. F f = . F norm Friction F norm ??? The “Normal Force” is a Supporting Force that is always perpendicular to the surface that the object rest on.

6. F norm For each of the following examples, label the direction of: the weight of the crate (F g ) and The normal force (F norm )

7. FgFg F norm Horizontal Surface FgFg F norm Inclined Surface FgFg F norm FaFa Vertical Surface Examples

8. FgFg F norm Horizontal Surface FaFa

9. Practice Problems Please open to page 128 (Ch. 5) and do #17 through 20 Now go to page 130 (Ch. 5) and do #22, 23, 24 Please also read CH 5 section 2 for homework tonight.