1. Chapter 15: Energy

2. Table of Contents Topic 1: Types of Energy
Kinetic Energy and Potential Energy
Topic 2: The 6 Forms of Energy
Mechanical, Thermal, Chemical, Electrical, Electromagnetic, Nuclear
Topic 3: Law of Conservation of Energy
“Energy cannot be created or destroyed”
Topic 4: Energy/Mass Relationship
E=mc2

3. Energy is related to “Work”
15.1 Energy and It’s Forms
Energy is related to “Work”
Energy – The ability to do work.
Energy is measured in Joules.
 W = F x d (Therefore) Energy = F x d
**Work is the transfer of energy**
A The sun gives off energy in the form of heat and light.
B Plants convert this heat and light energy into food that we can process and eat.
C People convert food energy into muscle movement

4. There are 2 GENERAL forms of Energy…

5. Types of Energy Kinetic Energy - Energy of motion. Kinetic Energy
Energy Type 1
Kinetic Energy - Energy of motion.
KE = ½ mv2
**Some KE trends to know:
When the mass is doubled, the KE is doubled.
When the velocity is doubled, the KE is quadrupled.
Kinetic Energy
is the energy contained in any moving object

6. Kinetic Energy Math Practice
1. A 70.0-kilogram man is walking at a speed of 2.0 m/s. What is his kinetic energy? 2. A 1400-kilogram car is moving at a speed of 25 m/s. How much kinetic energy does the car have?
KE =
m =
v =
Equation:
KE =
m =
v =
Equation:

7. 3. A 50. 0-kilogram cheetah has a kinetic energy of 18,000 J
A 50.0-kilogram cheetah has a kinetic energy of 18,000 J. How fast is the cheetah running? (Hint: Rearrange the equation to solve for v.)
KE =
m =
v =
Equation:

8. Work with a partner…
Complete the Kinetic Energy
questions on page 1

9. There are 2 forms of Energy…

10. Potential Energy Energy Type 2
Energy stored as a result of object’s position
**PE becomes KE when the object starts moving.
There are two types of potential energy.
1. Gravitational Potential Energy (GPE)
GPE depends on the height of an object. It increases as the object is raised up.
GPE = mgh (g = 9.8m/s2)
2. Elastic Potential Energy (EPE)
EPE is the potential energy of an object that is stretched or compressed (springs)
This diver has gravitational potential energy as she stands at the end of a diving board.

11. Potential & Kinetic Energy are Connected!

12. Math practice
1. What is the gravitational potential energy of a cat that weighs 40 N standing on a table that is 0.8 m above the ground?
2. What is the gravitational potential energy of a diver who weighs 500 N standing on a platform that is 10 m off the ground?

13. 3. What is the gravitational potential energy of a diver who has a mass of 61 kg standing on a platform that is 8 m off the ground?

14. Forms of Energy
There are 6 major forms of energy

15. Forms of Energy
Mechanical Energy- The energy associated with the motion and position of everyday objects.
**ME is NOT limited to machines.
ME = KE + PE
EX: speeding trains, more below

16. Kinetic Theory of Matter
Forms of Energy
2. Thermal Energy – The total PE and KE of every atomic particle in an object.
When an object’s atoms move faster, its thermal energy increases and the object becomes warmer.
Remember the
Kinetic Theory of Matter

17. Forms of Energy 3. Chemical Energy
Energy stored in the chemical bonds of a compound. When the bonds are broken, the released energy can do work.
EX: burning wood, batteries
This family is using the chemical energy of burning wood to produce thermal energy for heating marshmallows

18. Forms of Energy
4. Electrical Energy - energy associated with electric charges.
- EX: lightning, CD players
5. Electromagnetic Energy - A form of energy that
travels in the form of waves
- EX: visible light, X-rays

19. Forms of Energy
6. Nuclear Energy - The energy stored in an atom’s nucleus
EX: Nuclear fission: releases energy by splitting the nucleus
Ex: Nuclear fusion: releases energy when small nuclei combine to form a bigger nucleus
Energy released
Energy released

20. Match the Energy form to the Description
Write answers somewhere on your notes slides…. ___1. Falling rocks from the top of a mountain ___2. Release of energy from the Sun ____3. Energy released from food after it is eaten ____4. Batteries ___5. The energy that runs a refrigerator ____6. Nuclear fission reactors ____7. The rumble of thunder from a storm ____8. Rubbing your hands together ____9. Gasoline ___10. Food before it is eaten ___11. Lightening
Mechanical
Electrical
Heat
Radiant
Chemical
Nuclear
Sound

21. 15.2 Energy Conversion and Conservation
Energy can be converted from one form to another form.
When energy changes forms, the total energy remains unchanged.
Energy is converted from one form to another as this match is lit.

22. Conservation of Energy
The Law of Conservation of Energy:
“Energy cannot be created or destroyed”
In a closed system, during a reaction, the amount of energy at the beginning is the same as the amount of energy at the end.
Gravitational potential energy is converted to kinetic energy as the object falls.
Some gulls use energy conversion to obtain food by dropping oysters onto rocks.

23. Energy Conversion Calculations
Conservation of Mechanical Energy
(KE+PE)beginning = (KE+PE)end
A 10-kg rock is dropped and hits the ground below at a speed of 60 m/s. Calculate the GPE of the ball before it was dropped (You can ignore the effects of friction.)

24. 2. b. Calculate his speed when he enters the pool.
a. A diver with a mass of 70.0 kg stands at the top of a 3.0-m-high diving platform. Calculate his potential energy relative to the water surface while standing on the platform. (Hint: Assume the diver's initial vertical speed after diving is zero.)
b. Calculate his speed when he enters the pool.

25. 3. A pendulum with a 1. 0-kg weight is set in motion from a position 0
A pendulum with a 1.0-kg weight is set in motion from a position 0.4 m above the lowest point on the path of the weight. What is the kinetic energy of the pendulum at the lowest point? (Hint: Assume there is no friction.) m= v= h= g=

26. E = mc2

27. Energy and Mass Matter Energy Einstein’s theory of relativity E = mc2
E = energy m = mass
c = speed of light
Energy and mass are equivalent, and can be converted into each other.
Energy gets released as matter is destroyed, and matter can be created from energy.
The speed of light is a very large number, 3 x 108 m/s, and it is squared.

28. Energy and Mass
A tiny amount of matter can produce an enormous amount of energy
1 g of TNT = 2931 J of energy 
In nuclear fission (splitting atoms) and nuclear fusion (creating atoms), large amounts of energy are produced from very small amounts of matter. 
The law of conservation of energy has been modified to state that both mass and energy are conserved together.

29. E = mc2 problems
1. A sugar cube has a mass of 4.2g. If the mass of the sugar cube is converted into energy in your body, how many joules of energy would be produced?
2. The total annual energy consumption in the U.S.A. is 1.02x1019 joules. How much mass M would you need to produce an energy E = 1020 joules?

31. 15.3 - Nonrenewable Energy Resources
Fossil Fuels- were formed underground from the remains of once-living organisms
Ex: oil, natural gas, and coal
Currently, fossil fuels account for the great majority of the world’s energy use
Their use creates pollution 

32. Renewable Energy Resources
Renewable energy resources- resources that can be replaced in a relatively short period of time.
Most renewable resources originate directly or indirectly from the sun
Include: hydroelectric, solar, geothermal and wind energy

33. 1) Hydroelectric Energy
Hydroelectric Energy- obtained from flowing water
The natural flow of water in a river turns turbines
Most rely on dams build across rivers
A dam blocks the flow of water, storing potential energy that is converted into kinetic when the water is released
Low cost to produce, lack of pollution

35. 2) Solar Energy Solar Energy- sunlight converted into usable energy
Passive solar designs use sunlight to heat a building without using machinery
For example. Sunlight passing through the windows of a house may be absorbed by thick walls and then radiate thermal energy
In an active solar system, sunlight heats flat collection plates through which water flows
The heated water may be used directly for the buildings hot water needs, or it may be used to heat the house

36. **Solar Energy is non-polluting but for areas where cloudy days are frequent, solar energy is less practical

37. 3) Geothermal Energy
Geothermal Energy- thermal energy beneath the Earth’s surface
The geothermal power
plant pumps water into
the ground, where it turns
into steam. The steam is
then used to drive electric
generators.
Non polluting, but it not
widely available

38. Conserving Energy Resources
Energy Conservation- finding ways to use less energy or use energy more efficiently
Making appliances, cars, and even light bulbs more energy efficient is a way or reducing energy use while still enjoying its benefits
Energy-efficient purchases often cost more initially, but can save money in fuel costs over time
Page 466 Problems 1-5

39. 3/30 Do Now What does Potential mean? What is Energy?
In your own words, try your best to come up with definitions to the following…
What does Potential mean?
What is Energy?

40. HW: Pages 5 and 6 3/30 Agenda Do Now Notes: Types of Energy
Kinetic Energy and practice
Potential Energy and practice
HW: Pages 5 and 6

41. 3/31 Do Now
A 65 Kg linebacker has a kinetic energy of 12,000 J. How fast is the linebacker running?
KE =
m =
v =
Equation:

42. HW: Pages 7, 8, 9 3/31 Agenda Do Now Notes Forms of Energy
Conservation of Energy
HW: Pages 7, 8, 9

43. 4/1 Do Now
A 15 kg hypnotist’s pendulum moves side to side with a velocity of 1.5 m/s. Use the conservation of energy to determine how high up the pendulum travels.

44. HW: Page 10 4/1 Agenda E = mc2 and Practice Do Now
Additional practice problem
Quiz --- moved to Monday
Finish Notes Packet
E = mc2 and Practice
HW: Page 10

45. 4/4 Do Now
Write down 5 things you remember we learned or talked about last week

46. HW:Finish worksheets from today
4/4 Agenda
Do Now and check HWx2
Go over HW
Quiz
Finish Notes Packet
E = mc2 and Practice
Types of Energy
HW:Finish worksheets from today

47. 4/5 Do Now
In your own words… 1. Explain how Geothermal Energy works? 2. Explain how a Hydroelectric Dam works.

48. 4/5 Agenda
Do Now and check HW
Go over HW
Kahoot Quiz
HW: Study!

49. 4/8 Do Now
Write down 2 things you found especially interesting and/or memorable about yesterday’s film about renewable energy
If the USA could only use one of the Renewable Energy types you saw yesterday, which would be the best fit for the USA?
Why?

50. 4/6 Agenda Do Now Turn in Do Now Sheets Hand back work Go over tests
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