1. Friction

2. Warm up Come in quietly, get your journal from the appropriate bin, complete the following on the next available page: Draw the force diagram of Susie pushing her bike to the left with 400 N of force, and Roger pushing his bike to the right with 800 N of force. (Remember arrow size and direction) Draw the force diagram of a falling bowling ball weighing 20 N (Remember gravity is a force).

3. Two Masses Falling

4. Standards S8P3b. Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction.

5. Daily Goals Explain how friction works Give examples of the two types of friction Explain how friction can be helpful and harmful

6. Essential Question How does friction help football players?

7. Important Test Friday, Nov. 18 Practice Sheet #12 due Friday, Nov. 18 Study Guide due Friday, Nov. 18 for extra credit

8. Friction Friction - a force that opposes motion between two surfaces that are in contact

9. Direction of Friction Friction always works in the direction opposing motion

10. Friction

11. Types of Friction Two main types of friction – Static friction – occurs when a force is applied to an object but does not cause motion – Kinetic friction – Friction between moving surfaces

12. Warm Up Come in quietly, get your journals, and have a seat. Open your journals and complete the writing prompt “A World without Friction” You have ten minutes to be finished. (Not just starting, but completely finished. Finished means several complete sentences addressing the prompt). For a grade.

13. Kinetic Friction Three types – Rolling – Sliding – Fluid

14. Types of Friction

15. How to Increase/Decrease Friction Greater forces applied to the object increase friction

16. How to Increase/Decrease Friction Rougher surfaces on the objects increases friction VS.

17. How to Increase/Decrease Friction The amount of area in contact does not affect friction

18. How to Increase/Decrease Friction

19. Friction - Helpful

20. Friction - Harmful