2. “HAY DOC !!!”

3. Hay Doc !!!!

4. AIM: What is friction? What are the causes and consequences of friction? OBJ: Given activity sheets SWBAT explain what friction is and the causes and consequences of friction with 70% accuracy DN: HW Check- Friction & Gravity Booklet ACT: Complete Gravity Lesson (Free Fall video); Complete Friction 1 Activity Sheet; review results Work on Friction 2 Activity Sheet HW: Complete Friction 2 Activity Sheet and Speed Activity Sheet; SFFG Exam, April 28; NLSM Exam, May 28?

5. Speed Activity Sheet-A.K. 1. 2 2. 1 3. 1 4. 3 6. Stopped to rest, pump gas, get food, go to the bathroom, ran out of gas 7. Kinetic (mechanical) = energy of motion 8. Change propeller size, change airplane weight/mass, increase propeller turns, wind rubber band more, change length of wing

6. Speed Activity Sheet-A.K. 5. 9. same speed 10. trees move backward (to the left)

7. Friction 1 Activity Sheet 1. Sliding Friction: friction when two surfaces slide over each other. 2. Air Resistance is a type of fluid friction as an object falls through the air. 3. Rolling Friction: friction when an object rolls across a surface. To reduce friction, use wheels or ball bearings. 4. rf7. rf10. sf 5. ar8. rf 6. ar9. sf

8. Friction 2 Activity Sheet 1.Two surfaces are in contact and one (or both) surface(s) is/are in motion. 2. Friction moves opposite to the direction of motion. Friction slows down/gets object moving 3. More (static friction) 4. More 5. Wear out moving parts (tires), overheat an engine, rope burn.

9. Friction 2 Activity Sheet 6. Allows you to move, allows you to stop, start a fire 7. liquids & gases; fluid friction 8. press surfaces together (increase weight), roughness, no lubricants 9. Use lubricants (oils, grease), smoothness, do not press surfaces together (decrease weight) 10. Increase high Decrease medium low

10. a. Friction is caused by surfaces pressing together and in motion; So if a hovercraft rides on a cushion of air, 1) surfaces are not touching and 2) very little friction occurs (air is fluid friction) allowing the hovercraft to move faster than a boat. b. Pencil lead is a lubricant which reduces friction. c. Makes it easier to move heavy objects d. Fluid friction between the spacecraft and the atmosphere causes spacecraft to heat up rapidly; panels protect craft from burning up. Friction 2 Activity Sheet

11. e. Sliding friction causes surfaces to heat up f. Sliding friction causes surfaces to heat up g. Joints are smooth and lubricated