Here is the video for your notes. Be sure to pause, rewind, and stop as necessary.
Source: Langhans and various educators
1. Friction is defined as _____________________________________________________
2. Friction occurs when the ________________ and _______________ of two surfaces touch against each other.
3. The amount of friction depends on two factors…_________ and _________
4. Rougher surfaces typically have: MORE LESS friction. (circle one)
5. There is typically: MORE LESS friction between a heavy object and another surface than there is between a light object and another surface.
6. The two basic types of friction include __________________ friction, which is the friction that exists between two surfaces that are not moving and __________________ friction, which is the friction that exists between surfaces that are moving.
7. Generally, ____________________ friction is greater than sliding friction.
8. Rank these types of friction, greatest amount first, least amount last
Kinetic (sliding) Static
a. _____________________ b. ____________________
9. Explain how ball bearings reduce friction _________________________________
10. Explain how friction is useful in brakes and tires. __________________________
11. In each of the following situations, what effect will the change have on the amount of friction? Use the following choices: a) increase b) decrease c)no change
____________) The normal force (force pushing surfaces together) increases
____________) The roughness of only one surface is increased
____________) The surface area in contact increases
____________) A lubricant is added between the surfaces
____________) Static friction changes to kinetic friction
Questions – Fill In
12. Name a variable that has no effect on friction. ______________________________
13. Which direction does the frictional force always act? ______________
14. Name two ways that friction is harmful….__________________and _________________________________
15. Name two ways that friction is helpful…..________________ and ________________________________