Chapter 6 Test Review Energy, Work, and stuff

Answer on a notebook piece of paper. Show work when necessary.

1. What are the units for Force, Work, Power, KE, PE, Efficiency? 2. Give an example of applying a work, but doing no work? 3. How much work do you do when you apply twice the force? 4. How much work do you do when you move an object twice the distance? 5. How much work do you do when you apply twice the force for twice the distance? 6. What happens to the power when you do work in a shorter period of time? 7. What happens to the power when you do twice the work in twice the time? 8. Exert 4-N for a distance of 1-m in 2 seconds and deliver a power of? (show work) 9. An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised four times as high, it gains how much PE? 10. Which has greater kinetic energy, a car traveling at 20 km/h or a car of half the mass traveling at 40 km/h? 11. What are the two types of PE? Give examples. 12. A car moves 2 times as fast as another identical car. Compared to the slower car, the faster car has how much more/less KE? 13. A 4-kg mass has 120 J of potential energy with respect to the ground. Approximately how far is it located above the ground? (show work) 14. A 4-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground? (show work) 15. Which requires more work: lifting a 40-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m? 16. Which requires more power : lifting a 40-kg sack vertically 2 m in 2 seconds or lifting a 25-kg sack vertically 4 m in 4 seconds? (show work) 17. Draw a picture of a pendelum and show when the KE is largest, PE is largest, and when they are equal. 18. Draw a picture of a ball thrown into the air and show when the KE is largest, PE is largest, and when they are equal. 19. Why aren’t machines 100% efficient? 20. What is the purpose of a machine? 21. With a pulley, if you pull one end of a rope downward with a 20 N force a distance of 2 meters, how high will you lift a 200 N load? 22. In a machine where a small piston is pushed down 20 cm and a large piston on the other side is raised 1 cm. If the small piston is pushed with 100 N, what is the force that the big piston could push? 23. What was the purpose of the “Running up the stairs lab?” What did we change? 24. In the Egg Drop Contest: a. What happened to the acceleration? b. What happened to the velocity? c. How did you determine the final velocity? d. How did you determine the final momentum? e. What two factors affect the air drag? f. What affects the impulse? g. How did you determine the PE? KE?