1. What is Energy?

2. What is Energy?
The ability to do work or cause change.

3. Work Easiest to start with the notion of work Work = Force X Distance
Lift a box from the floor, you apply a force to overcome gravity
Multiply that force by the distance through which you apply the force and you calculate the amount of work accomplished

4. Is this Work?

5. Work Unit is the JOULE A Joule is a newton-meter Kgm2 /s2
A newton is a unit of force Mass times meters per second persecond times a distance in meters

6. Power The rate at which work is done
Takes more power to run up the stairs than to walk up the stairs, but the energy consumed is the same in either case

7. Power Unit is the WATT A Watt is a newton--meter per second
Think of 100-Watt light bulb
Bigger units are kilowatts and megawatts
Utility sells energy in kilowatt-hours
1 KWh = 1000 Joules/second times 3600 Seconds = 3.6 X 106 Joule

8. What are the different forms of Energy?
Energy has a number of different forms, all of which measure the ability of an object to do work on or change another object.
In other words, there are different ways that an object can possess energy.

9. What are the different forms of Energy?
Mechanical Energy
Kinetic Energy
Potential Energy
Elastic Potential Energy
Thermal, or heat energy
Chemical Energy
Electrical Energy
Electrochemical Energy
Electromagnetic Energy (light)
Sound Energy
Nuclear Energy

10. Define Potential Energy
Potential energy is energy due to position or stored energy. Potential energy is also called gravitational potential energy.
If we lift an object from the floor into the air, it has the potential to do work for us (Gravitational PE)

11. Potential Energy This ability to do work is called POTENTIAL ENERGY
Other forms of potential energy include the compression of a spring (Elastic PE), the stored energy in coal or oil, the stored energy in a uranium nucleus (Chemical PE)

12. Give an example of potential energy
By stretching a rubber band, or a spring you give it elastic potential energy. A vase on a shelf has stored potential energy. A football being held by a quarterback has potential energy until it is thrown and it turns into kinetic energy.

13. Potential Energy Gravitational potential energy is simple to calculate
Gravitational Potential Energy = weight X height

14. Define Kinetic Energy
Kinetic energy is the energy of motion. Kinetic energy is measured by how much is work done to put an object in motion or to rest.

15. Give an example of kinetic energy
A basketball player has kinetic energy. The movements that she does show the energy that is being displayed while she is moving. When you are running, walking, or jumping, your body is exhibiting kinetic energy.

16. Kinetic Energy The energy of moving objects
Kinetic Energy = 1/2 Mass X Speed2

17. Give an example of something that has both potential and kinetic energy.

18. Work-Energy Theorem
Work done on an object can give the object either potential or kinetic energy or both
If we do work on an object to lift it into the air, we give it potential energy
If we do work on an object and set it into motion, we give it kinetic energy
The work-energy theorem relates to the second case

19. Work-Energy Theorem
If we do work on an object and set it into motion without changing the object’s potential energy, the work done appears as kinetic energy of the object

20. Describe Conservation of Energy
Energy cannot be created or destroyed; it can only be changed from one of form of energy to another form. 
The amount of energy stays the same. 

21. Conservation of Energy
Perhaps the most important discovery of the past two centuries
In the absence of external work input or output, the energy of a system remains unchanged. Energy cannot be created or destroyed.
Remember from Einstein, that mass is a form of energy

22. Give an example of something that has both potential and kinetic energy.
A waterfall has both kinetic and potential energy. The water at the top of the waterfall has stored potential energy. Once the water leaves the top of the waterfall, the potential energy is changed into kinetic energy.

23. Kinetic-Potential Energy Conversions
As a basketball player throws the ball into the air, various energy conversions take place.

24. Ball speeds up
Ball slows down

25. Click this link for more information about potential & kinetic energy
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26. Describe Conservation of Energy
Click here for more examples of Conservation of Energy:
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27. Vocabulary Words energy mechanical energy heat energy chemical energy
electromagnetic energy
nuclear energy
kinetic energy
potential energy
gravitational potential energy
energy conversion
Law of Conservation of Energy