1. Chapter 15
Energy

2. Energy: The ability to do work.
Energy and Work
Energy: The ability to do work.

3. Work = Force x distance W = F x d The transfer of energy as
the result of motion.
(Unit of Work is the Joule)
Work = Force x distance
W = F x d

4. Joule (J) Unit of Energy and Work. W = F • d Joule = Newton • meter
J = (kg • m/s²) • m

5. Energy that appears in the
Kinetic Energy (KE)
Energy that appears in the
form of motion.

6. Kinetic Energy (KE) m
KE = ½ mv2

7. A 70. 0-kilogram daemon is walking at a speed of 2. 0 m/s
A 70.0-kilogram daemon is walking at a speed of 2.0 m/s. What is his kinetic energy?

8. KE = 140J Given: m = 70.0kg v = 2 m/s Find: KE = ?
Equation: KE = ½ mv2
Solve: KE = ½ (70.0kg)(2 m/s)2
KE = 140J

9. Energy that an object has as the result of its position or condition.
Potential Energy (PE)
Energy that an object has as the result of its position or condition.

10. Gravitational Potential Energy (GPE)
An object's gravitational potential energy depends on its mass, its height, and the acceleration due to gravity.

11. g = acceleration due to gravity(9.8m/s2)h
PE = mgh
m = mass
h = height
g = acceleration due to gravity(9.8m/s2)

12. Suppose the diver at the top of a 10
Suppose the diver at the top of a 10.0-meter-high diving platform has a mass of 50.0 kilograms.

13. GPE = 4900J Given: m = 50.0 kg h = 10 m g = 9.8 m/s2 Find: GPE = ?
Equation: GPE = mgh
Solve: GPE = (50.0kg)(9.8 m/s2)(10m)
GPE = 4900J

14. Elastic Potential Energy
The potential energy of an object that is stretched or compressed.

15. Forms of Energy
The major forms of energy are mechanical energy, thermal energy, chemical energy, electrical energy, electromagnetic energy, and nuclear energy.

16. Kinetic Energy and Potential Energy ME = KE + PE
Mechanical Energy
Kinetic Energy
and
Potential Energy
ME = KE + PE

17. Thermal Energy
The total potential and kinetic energy of all the microscopic particles in an object

18. Chemical Energy
The energy stored in
chemical bonds.

19. Energy associated with electric charges.
Electrical Energy
Energy associated with electric charges.

20. Electromagnetic Energy
Form of energy that travels through space in the form of waves.

21. The energy stored in atomic nuclei.
Nuclear Energy
The energy stored in atomic nuclei.

22. Nuclear Fission

25. Nuclear Fusion

26. Nuclear Fusion

28. Math Practice Page 448, Probs:1-3
Homework
Math Practice Page 448, Probs:1-3
Section 15.1
Worksheet Due: 4/29/10

29. Example #1: Mr. Clune weighs 100N. He walks up some stairs 5m high
Example #1: Mr. Clune weighs 100N. He walks up some stairs 5m high. How much work does he do???
Given: F = 100N
d = 5m
Find: W = ?
Equation: W = F x d
Solve: W = ( 100N ) x ( 5m )
W = 500J

30. Example #2: Amy picks up her physical science book, that has a mass of 2.0kg, to a height of 1.5m. How much work did Amy do????
Given: m = 2.0kg d = 1.5m a = 9.8 m/s²
Find: F = ??
W = ??
Equations: W = F x d F = m x a
W = ( m x a ) x d
Solve: W = {( 2.0kg) x (9.8 m/s²)} x (1.5m)
W = 29.4J

31. Law of Conservation of Energy
Can change from one form to another.
Can never be created or destroyed.
Total energy of the universe remains the same.

32. Potential Energy + Kinetic Energy
Mechanical Energy =
Potential Energy + Kinetic Energy
E = PE + KE
KE = 0
PE = max
KE = 0
PE = max
KE = max
PE = 0

33. Pole Vault
Kinetic Energy

34. Elastic Potential Energy

35. Kinetic Energy

36. Gravitational Potential Energy

37. E - Energy
m - mass
c – speed of
light

38. PE
Work
KE + PE
KE + PE

39. One Calorie = 4180 joules
One hour of running
1000 calories

40. Homework 15-2
Section 15-2
Worksheet
Due: 4/7/09

41. Nonrenewable Energy
A source of energy that exists in limited quantities and, once used, cannot be replaced except over the course of millions of years.

42. Nonrenewable Energy
Nonrenewable energy resources include oil, natural gas, coal, and uranium

43. Renewable Energy
A source of energy that can be replaced in a relatively short period of time.

44. Renewable Energy
Renewable energy resources include hydroelectric, solar, geothermal, wind, biomass, and, possibly in the future, nuclear fusion.

45. Hydroelectric

46. Solar

47. Geothermal

48. Wind

49. Biomass

51. Homework 15-3
Section 15-3 Worksheet
D: Due: 4/8/09

52. Homework 15-3 Section 15-3 Worksheet D: Due: 4/8/09 F: Due: 4/7/07
D Test: 4/9/08
F Test: 4/11/08

53. Homework 15 -3
Section 15-3
Word-wise/Math
Worksheets
Due: 5/5/10
D Test: 5/6/10
E Test: 5/7/10

54. Temperature and Heat
Temperature: The measure of the average kinetic energy of the particles in a sample of matter.

55. The total energy of the particles
Thermal Energy
The total energy of the particles
in a material.
25ºC
25ºC

56. The flow of Thermal Energy.
Heat
The flow of Thermal Energy.

57. Heat is the flow of Thermal Energy from an area of
High Temperature
to one of
Low Temperature.

58. Thermal Pollution
Waste you can’t see!!!

59. Thermal Pollution: Occurs when waste heat significantly changes the temperature of the environment.
Adding warm water to lakes, rivers and oceans can change the environment. How?

60. Homework 5-2
Section Wrap-up
Page: 137
Page: 140
Due: 11/7/05

61. Projects Due Tomorrow 11/04/05

62. Homework 5-3
Section Wrap-up
Page: 140
Due: 10/17/02

63. Measuring Thermal Energy
Type of Material
Mass of Material
·      Temperature

64. Material
Water
Metal

65. Specific Heat [C, J / (kg • K)]
The amount of energy it takes to it takes to raise the temperature of 1 kg of material 1 Kelvin. ( K = C )
It takes 4184 joules of energy to raise the temperature of 1 kg of water, 1C.

66. Material Specific Heat Water 4184 J / (kg • K) Alcohol
Material
Specific Heat
Water
J / (kg • K)
Alcohol
J / (kg • K)
Aluminum
920 J / (kg • K)
Graphite(Carbon)
710 J / (kg • K)
Sand
664 J / (kg • K)
Iron
450 J / (kg • K)
Copper
380 J / (kg • K)
Silver
235 J / (kg • K)

67. Calculating Thermal Changes
Change in Thermal Energy - Q
Mass - m
Change in Temperature -  T
Specific Heat - C
Q = m • T • C
T = Tfinal - Tinitial

68. Example: Mr. Clune wants to bring 1 kg of water to boiling for his afternoon tea. The temperature of the water out of the tap is 10C. How much Thermal Energy does he have to add to the water?

69. Q = 377,000 J or 377 kJ Given: m = 1 kg Find: Q = ? Tinitial = 10C
Tfinal = 100C
C = 4184 (J / (kg • C ) )
Equation: Q = m • T • C
Q = m • (Tfinal - Tinitial) • C
Solve:
Q = (1 kg) • (100C -10C) • 4184(J/(kg • C)
Q = (1 kg) • (90C) • 4184 (J/(kg • C)
Q = 377,000 J or 377 kJ

70. Example: Do the same problem as the one above but use sand instead.
Given: m = 1 kg Find: Q = ?
Tinitial = 10C
Tfinal = 100C
C = 664 (J / (kg • C ) )
Equation: Q = m • T • C
Q = m • (Tfinal - Tinitial) • C
Solve:
Q = (1 kg) · (100C -10C) · 664(J/(kg.C)
Q = 60,000 J or 60 kJ

71. Homework 5-4
Practice Problem: 1-2
Page:143
Section Wrap-up
Page: 144
Due: 11/09/05
Test on 11/15/05

72. Homework 5-5
Vocabulary: 1-10
Page:147
Review Questions:1-25
Page:
Due: 11/22/04
Test: 11/23/04