1. Energy

2. DEFINITION the ability to cause a change
common measurement unit = Joule (J)

3. FORMS energy exists in many different forms: 1. potential 2. kinetic
3. mechanical
4. heat
5. chemical
6. nuclear
7. electrical
8. light
9. sound

4. (Gravitational) Potential Energy
abbreviations: PE, GPE, and PEgravitational
energy stored in a non-moving object due to its position, shape, or composition in a gravitational field

5. Kinetic Energy abbreviation: KE energy of motion all moving objects
have kinetic energy

6. Mechanical Energy total potential energy & kinetic energy of an object
ME = PE + KE

7. Heat
Energy that moves from hot objects to cooler ones

8. Chemical Energy
energy stored in chemical bonds

9. Nuclear Energy
Energy stored in the nucleus of an atom

10. Electrical Energy
Energy of moving electrons

11. Light Energy
Energy contained in electromagnetic waves

12. Sound Energy
Energy produced by vibrating objects

13. Potential Energy Word Problems
A 4 kg rock is sitting on a 3 m ledge. How much gravitational potential energy does it have?

14. GIVENS: m = 4 kg h = 3 m g = 9.8m/s2 UNKNOWN: PE EQUATION: PE = mgh SUBSTITUTION: PE = (4 kg) x (9.8m/s2) x (3 m) SOLUTION: J

15. Kinetic Energy Word Problems
A 3 kg ball is rolling at a velocity of 2 m/s. How much kinetic energy does it have?

16. GIVENS: m = 3 kg v = 2 m/s
UNKNOWN: KE
EQUATION: KE = ½ mv2
SUBSTITUTION: KE = ½ (3kg)(2m/s)2
SOLUTION: 6kgm/s2 = 6 J

17. LAW of CONSERVATION of ENERGY
Energy cannot be created or destroyed, BUT it can be transferred from one object to another AND it can be changed, or converted, from one form to another

18. Energy Transfer

19. Occurs when one object passes some of its energy to another object
First object loses energy; second object gains energy
3 main ways: conduction, convection, and radiation

20. Conduction Energy is transferred within an
object or between objects that
are touching
As particles in objects collide,
their energy is transferred

21. Convection Fluids (liquids & gases) transport energy from one place to
another
Forms convection
currents

22. Radiation transfer of energy through electromagnetic waves
radiation is felt as energy
is absorbed by a material

23. Energy Conversions AKA energy transformations
Change of one form of energy into another

24. example

25. Electric Fan Electrical → kinetic When you plug in the fan,
electricity causes the
blades to move