1. Potential and Kinetic Energy

2. What is Energy? Energy – the ability to do work 2 categories of energy
does NOT have mass or take up space
Measured in the unit joules
2 categories of energy
Potential Energy
Kinetic Energy

3. Forms of Energy Energy can take different forms Potential Energy
Kinetic Energy
Chemical
stored energy in bonds
Thermal
energy of moving particles (heat)
Elastic
stored energy due to tension
Mechanical
energy found in objects in motion
Nuclear
stored energy in the nucleus of an atom
Electrical
movement of electrons
Gravitational
stored energy due to position above ground
Sound
longitudinal waves that are heard
EM Waves
all the waves in the EM spectrum move

4. Law of Conservation of Energy
Law of Conservation of Energy – no new energy is created nor destroyed, it’s just transferred from one form to another

5. Potential Energy Potential Energy – stored energy of position
Has the “potential” to do something

6. Kinetic Energy
Kinetic Energy – energy of motion

7. Energy Transformation
When you lift the marble off the ground it gets potential energy because of its height

8. Energy Transformation
As the marble moves down the track, it loses potential energy, and is converted into kinetic energy

9. Energy Transformation
The marble slows down as it goes uphill because kinetic energy is being changed back into potential energy

10. Energy Transformation
Animated Roller Coaster

12. Energy Conversion

13. Energy Conversion

14. Energy Conversion

15. Energy Conversion

16. What kind of energy transformations are occurring here?

17. Potential or Kinetic?
Moving car
Kinetic

18. Potential or Kinetic?
Tree branch
Potential

19. Bent car fender Potential
Potential or Kinetic?
Bent car fender
Potential

20. Balloon filled with water
Potential or Kinetic?
Balloon filled with water
Potential

21. Potential or Kinetic?
Log of wood
Potential

22. Balloon squirting around
Potential or Kinetic?
Balloon squirting around
Kinetic

23. Person inside a moving car
Potential or Kinetic?
Person inside a moving car
Kinetic

24. Potential or Kinetic?
Both

25. Potential or Kinetic?
Kinetic

26. Potential or Kinetic?
Kinetic

27. An airplane circling in preparation for landing
Potential or Kinetic?
An airplane circling in preparation for landing
Kinetic

28. A pile of coal that will be used for fuel
Potential or Kinetic?
A pile of coal that will be used for fuel
Potential

29. An unlit firecracker Potential
Potential or Kinetic?
An unlit firecracker
Potential

30. Glucose stored in plants as a result of photosynthesis
Potential or Kinetic?
Glucose stored in plants as a result of photosynthesis
Potential

31. Burning log of wood Kinetic
Potential or Kinetic?
Burning log of wood
Kinetic

32. A dam holding back a river’s water
Potential or Kinetic?
A dam holding back a river’s water
Potential

33. A marble rolling down the aisle
Potential or Kinetic?
A marble rolling down the aisle
Kinetic

34. A new car battery Potential
Potential or Kinetic?
A new car battery
Potential

35. An ant crawling across a sandwich
Potential or Kinetic?
An ant crawling across a sandwich
Kinetic

36. A tennis racket about to crash down on a ball
Potential or Kinetic?
A tennis racket about to crash down on a ball
Potential

37. Energy at rest Potential
Potential or Kinetic?
Energy at rest
Potential

38. A mousetrap set and ready to spring
Potential or Kinetic?
A mousetrap set and ready to spring
Potential

39. PE= Joules (J)

40. Example
An 80kg man is jogging at a rate of 4m/s. He has kinetic energy. Calculate it:
KE = ½ x mass x velocity2
KE = ½ x 80kg x (4m/s)2
KE = ½ x 80 x 16
KE = 40 x 16
KE = 640 J

41. Example
A 420kg boulder sits on top of a 100m cliff. What is the potential energy?
PE=mgh
PE = (420kg)(9.8 m/s2)(100M)
PE=411,600 J