This document contains 10 statements about friction and whether they are true or false. It addresses several concepts related to friction including that friction always builds heat, rough surfaces create more heat than smooth surfaces, and oil and grease can reduce friction. The majority of the statements provided are true, except for numbers 2, 5, 6, and 9 which are false.

1. True or False
1. Friction always builds heat.
2. Smooth surfaces build more heat than rough
surfaces do.
3. Oil and grease can reduce friction.
4. Friction is always present.
5. Kinetic friction is greater than static friction.
6. Rolling friction is greater than sliding friction.
7. It takes more work to move something on a
lubricated surface.
8. All surfaces are smooth.
9. You would oil a bicycle wheel to increase its friction.
10. Friction is always harmful.
True
False
True
True
False
False
False
False
False
False

2. ReviewReview
•Force
•Friction
•Static Friction
•Kinetic Friction
•Factors that affect friction

3. Elastic ForceElastic Force
•Force produced by
stretching/compressing
elastic materials

4. Elastic ForceElastic Force
•Felastic = kd

5. Elastic ForceElastic Force
• What factors affect elastic
force?
• Type of material (k)
• Stretch length/compression
distance (d)
• Linear relationship

6. Elastic ForceElastic Force
• What factors affect elastic
force?
• Type of material (k)
• Stretch length/compression
distance (d)
• Linear relationship