Friction Section Review 1. What is Friction? A. a force creating motion B. a force of motion C. a force opposing motion D. velocity ANSWER C. A force opposing motion 2. What are two factors that determine the amount of friction? A. the force and roughness of the surfaces B. hills and valleys and the roughness of the surfaces C. the force and how much surface comes n contact D. the force and weight exerted on the surfaces. ANSWER A. the force and roughness of the surfaces. 3. What kind of friction takes place between moving surfaces? a. kinetic b. static c. smooth d. rough ANSWER A. Kinetic 4. What type of kinetic friction is used to write with a pencil? a. static b. sliding c. rolling d. smooth Answer B. sliding 5. Which of these is opposed by kinetic friction? A. a book sitting on a table B. a cat standing in the yard C. a child leaning on a building D. a box sliding on the floor. ANSWER D. a box sliding on the floor. Kinetic friction occurs when two objects are moving in opposite directions of each other. 6.Use the figure to help answer the question: Look at Figure A below. Why does the block not move? a. no force applied b. force of friction c. surface friction d. kinetic friction ANSWER A. No force is applied 7. Use the figure to help answer the question: Look at Figure B below. The block does not move. What force keeps the block from moving? a. rolling kinetic friction b. sliding kinetic friction c. static friction d. kinetic friction ANSWER C. static friction 8. In which of the following activities is friction helpful? A. soil erosion B. car tires moving a car forward C. engine parts wearing out D. holes developing in your socks ANSWER B. car tires moving your car forward. 9. What would happen if you tried to walk without friction? a. You would slip and fall. b. You would get lost. c. You would change direction. d. You would go slower. ANSWER A. you would slip and fall 10. How do lubricants affect friction? a. increases friction b. decreases friction c. increases force d. decreases force ANSWER B. decrease friction 11. How does sand on an icy road keep cars from skidding? a. It makes surfaces hotter B. it makes surfaces smoother C. it makes surface rougher D. it makes surfaces nicer ANSWER C. it makes surfaces rougher 12. Which of these is opposed by static friction? A. a chair sliding on the floor B. a pencil rolling on the table C. a dog running in the yard D. a worker pushing a non moving box ANSWER D. a worker pushing a non-moving box 13. Why is it easy to slip when there is water on the floor? A. the water is very wet B. the water creates static friction C. the water acts as a lubricant D. the water creates hills and valleys on the floor ANSWER C. the water acts as a lubricant 14. In which of the following is friction harmful? A. brakes stopping a car B. an eraser erasing C. car engine parts wearing out D. a person walking ANSWER C. car engine parts wearing out. 15. Which would NOT be a way to reduce friction? A. pouring sand on ice B. lubricating with oil C. using sandpaper D. using ball bearings ANSWER A. pouring sand on ice. 16. What would be the benefit of using snow tires on a car? A. they reduce the amount of friction B. they’re for snow……….duh C. they increase friction D. they create rolling kinetic friction ANSWER C. they increase friction 17. What is one way to increase friction when sanding a piece of wood? a. Press harder. b. Freeze the wood. c. Use oil. d. Use ball bearings. ANSWER A. press harder.