2. Energy Chapter 15

3. What is energy? DefinedDefined as the ability to do work or the ability to cause change. MeasuredMeasured in joules. CanCan occur in many forms.

4. Kinetic Energy Energy of motion All moving objects possess kinetic energy Can change from one type to another

5. Factors which affect kinetic energy: MASSMASS K.EK.E = ½ mv 2 VELOCITYVELOCITY

6. Potential Energy EnergyEnergy stored in an object due to its position. Examples:Examples:

7. Gravitational potential energy DependantDependant on the weight of the object and its height above some reference point. Formula:Formula:

8. Elastic Potential Energy PotentialPotential energy due to to the physical distortion of an object. DependsDepends on: –Type –Type of material –Amount –Amount of distortion

9. Six main forms of energy:

10. 1. Mechanical energy Energy associated with motion:Energy associated with motion:

11. 2. Heat energy Internal motion of particles of matter that often causes a change in temperature.Internal motion of particles of matter that often causes a change in temperature.

12. 3. Chemical energy EnergyEnergy released or stored when atoms are bonded together. BondsBonds can be broken to release this energy.

13. 4. Electromagnetic energy A form of energy that travels through space in the form of waves.A form of energy that travels through space in the form of waves.

14. 5. Nuclear energy FoundFound in the nucleus of the atom MostMost concentrated form of energy ReasonReason for the brightness and heat of the sun NuclearNuclear Nuclear link

15. 6. Electrical energy Energy associated with electrical charges or moving electrons.

16. Energy conversions AllAll forms of energy can change from one form to another. Examples:Examples:

17. Conservation of Energy Energy can be neither created nor destroyed.

18. Calculations WhenWhen friction is absent or small enough to be ignored, total mechanical energy = KE + PE ProblemsProblems 1-3 page 458

19. Theory of Relativity DevelopedDeveloped by Albert Einstein in 1905. EnergyEnergy is directly related to mass. E= mc 2

20. Energy Resources Nonrenewable: –C–C–C–Cannot be replaced after being used up. Examples:

21. Renewable resources CanCan be replaced in a relatively short period of time. Examples: HydroelectricHydroelectric SolarSolar WindWind BiomassBiomass ThermalThermal

22. Hydroelectric energy Energy obtained by damming a river and controlling the flow. Potential energy converted to kinetic converted to electric

23. Solar energy Using sunlight as an energy source on earth. A huge amount of energy available, but problems include storage and dependence on climate.

24. Wind power Relatively unlimited amount of energy available. Problem: What if it is not windy?

25. Geothermal energy UsingUsing the heat beneath the Earth’s surface.

26. Hydrogen fuel cells and biomass Hydrogen fuel cells: a way to generate electricity by reacting hydrogen with oxygen. Biomass: using living organisms to produce energy.

27. assignment Page 469-470Page 469-470 1-10, 12, 13, 14, 18, 21, 23, 25, 27, 28, 29, 321-10, 12, 13, 14, 18, 21, 23, 25, 27, 28, 29, 32