energy, work, and power review

Energy and PowerEnergy and Power

1. Energy is the ability to cause __________.1. Energy is the ability to cause __________.

2. Energy in the form of motion is . . . 2. Energy in the form of motion is . . .

3. Draw an example of kinetic energy3. Draw an example of kinetic energy

4. Write this down:4. Write this down:

KE = KE = ½½ mv mv22

(don’t forget to divide by 2)(don’t forget to divide by 2)

KE = ½ mvKE = ½ mv22

KE = KE = mvmv22

22

KE = KE = mvvmvv

22

5. If a man has a mass of 5. If a man has a mass of 80 kg80 kg

and is falling at and is falling at 10 m/s10 m/s,,

what is his kinetic energy?what is his kinetic energy?

6. Kinetic energy depends on . . .6. Kinetic energy depends on . . .

ANDAND

7. The S.I. unit for energy is the __________.7. The S.I. unit for energy is the __________.

8. Energy stored in a 8. Energy stored in a motionless object is . . .motionless object is . . .

9. What are the three forms9. What are the three forms

of potential energy?of potential energy?

Gravitational Potential Energy (GPE)Gravitational Potential Energy (GPE)

Having gravitational energy usually leads to Having gravitational energy usually leads to a change in kinetic energy . . .a change in kinetic energy . . .

10. Draw an example of GPE10. Draw an example of GPE

Jabba the Hutt vs. Mr. TJabba the Hutt vs. Mr. T

on the Empire State Buildingon the Empire State Building

11. Who has more GPE?11. Who has more GPE?

WHY??WHY??

12. What two factors affect GPE?12. What two factors affect GPE?

vs.vs.

vs.vs.

13. Write this down:13. Write this down:

GPE = mghGPE = mgh

(gravity = 9.8 m/s(gravity = 9.8 m/s22))

14. What is the GPE of a girl on a roller 14. What is the GPE of a girl on a roller coaster if her mass is coaster if her mass is 70 kg 70 kg and her and her height off the ground is height off the ground is 100 meters100 meters??

Chemical PotentialChemical Potential

15. Draw an example of chemical potential15. Draw an example of chemical potential

Elastic potentialElastic potential

16. Draw an example of elastic potential16. Draw an example of elastic potential

Energy just changes fromEnergy just changes from

one form to another.one form to another.

17. What types of energy are being 17. What types of energy are being transferred in this picture?transferred in this picture?

18. What types of energy 18. What types of energy are being transferred in are being transferred in

this picture?this picture?

19. What types of 19. What types of energy are being energy are being transferred in this transferred in this

picture?picture?

(Pretend the sled is at (Pretend the sled is at the top of a hill.)the top of a hill.)

20. What law states that energy can 20. What law states that energy can never be created or destroyed, never be created or destroyed,

only transferred to another form? only transferred to another form?

Law of Conservation of EnergyLaw of Conservation of Energy

21. Mechanical Energy = ______ + ______21. Mechanical Energy = ______ + ______

22. Friction converts mechanical energy into 22. Friction converts mechanical energy into __________ energy.__________ energy.

23. What is the transfer 23. What is the transfer of energy that occurs of energy that occurs when a force makes when a force makes

an object move?an object move?

24. For work to occur, an object must _____.24. For work to occur, an object must _____.

25. Is #9 doing work on #93?25. Is #9 doing work on #93?

26. For work to occur, the motion of the 26. For work to occur, the motion of the object must be in the _____________ object must be in the _____________

as the applied force.as the applied force.

27. Is the man receiving the punch doing work?27. Is the man receiving the punch doing work?

Why or why not?Why or why not?

28. Write this down28. Write this down

w = Fdw = Fd

w = force x distancew = force x distance

29. If this dude lifts a weight with 29. If this dude lifts a weight with 900 N900 N of of force upward force upward 3 meters3 meters, what work has he , what work has he

done?done?

30. Draw a picture of a person doing work 30. Draw a picture of a person doing work on an objecton an object

The story of kinetic and potential energy

31. What is the amount of work done in a 31. What is the amount of work done in a certain amount of time?certain amount of time?

32. Who probably uses 32. Who probably uses more power, A or B?more power, A or B?

AA BB

WW33. What is the S.I. Unit for power?33. What is the S.I. Unit for power?

34. List and define Newton’s 3 laws of motion34. List and define Newton’s 3 laws of motion

35. What is the difference b/w a theory 35. What is the difference b/w a theory and a scientific law?and a scientific law?

P.S. Know your experimental variables:P.S. Know your experimental variables:

Independent, Dependent, Constant,Independent, Dependent, Constant,

andand

ControlControl