1. Chapter 5: Energy and Energy Resources

2. Section 1: What is Energy?
Energy and Work—working together
Energy: ability to do work
Measured in SI unit joule

3. Section 1: What is Energy?
Kinetic Energy is Energy in Motion
Kinetic Energy: Energy in motion
Kinetic Energy Depends on Speed and Mass
Kinetic Energy = mv2 / 2
m= mass; v=object’s speed
The faster something is moving the more kinetic energy it has.
The more massive something is the more kinetic energy it has.
Speed has more effect than mass

4. Section 1: What is Energy?
Potential Energy Is Energy of Position
Potential Energy: energy an object has because of shape or position
Gravitational Potential Energy Depend on Weight and Height
Depends on distance from earth’s surface
Depends on weight of object
Calculating Gravitational Potential Energy
GPE = weight x height
Expressed in joules

5. Section 1: What is Energy?
Mechanical Energy Sums it All Up
Mechanical Energy: total energy of motion and position of an object
Could be all potential energy, all kinetic energy or some of both
ME = PE + KE
When PE increases/decreases KE does the opposite

6. Section 1: What is Energy?
Forms of Energy
Thermal
Chemical
Electrical
Sound
Light
Nuclear

7. Section 1: What is Energy?
Thermal Energy
Total energy of particles hat make up an object
High temperatures make particles move faster
Faster moving particles (more kinetic energy) leads to more thermal energy

8. Section 1: What is Energy?
Chemical Energy
Energy of a compound that changes as its atoms are rearranged to form a new compound
Form of potential energy
Examples: food, gasoline

9. Section 1: What is Energy?
Electrical Energy
Energy of moving electrons
Form of Kinetic energy

10. Section 1: What is Energy?
Sound Energy
Caused by an object’s vibrations
Form of kinetic and potential energy

11. Section 1: What is Energy?
Light Energy
Produced by vibrations of electrically charged particles

12. Section 1: What is Energy?
Nuclear Energy
Energy associated with changes in nucleus
Two nuclei join together or nucleus split

13. Section 2: Energy Conversions
Energy Conversion: change form of energy into another
Any form can be converted into any other form

14. Section 2: Energy Conversions
From Kinetic to Potential and Back
Example—Jumping on a trampoline
Jumping—Movement is Kinetic Energy
In Air—Gravitational potential energy
Trampoline—Stretching is gravitational potential energy
Example—Motion of A Pendulum
Potential Energy converted to kinetic energy

15. Section 2: Energy Conversions
Conversion Involving Chemical Energy
Chemical Energy in food converted to energy for the body
Sun’s energy converted into sugar— chemical energy through photosynthesis
Carbon dioxide + Water Yields Sugar + Oxygen

16. Section 2: Energy Conversions
Conversions Involving Electrical Energy
Electrical energy easily converts to other forms of energy
Example: Hair Dryer
Electrical Energy Enters—Converts to kinetic energy
Electrical Energy—Converts to Thermal Energy
Electrical Energy—Converts to Sound

17. Section 2: Energy Conversions
Energy and Machines
Machines transfer your energy
Energy can be converted to other forms of energy
Machines are energy converters
Kinetic energy may be converted into other forms

18. Section 2: Energy Conversions
Why Energy Conversions Are Important
Making Energy Useful
Converts energy to a useful form
Making Conversions Efficient
Energy efficient—compares amount of energy before conversion with the amount of useful energy after conversion