Energy

Energy• The ability to

do work and overcome resistance.

• The ability to cause change.

EnergyWork – The relationship between force on an object and distance moved.

W = FdWork = Force · Distance

EnergyUnit of Energy = Joule• Since the unit of force is a Newton

and distance is measured in meters, a Joule is a N · m.

James Prescott Joule1818 -1889

Work – Energy Theorem

W = ∆ EK

Energy

Energy is Classified as either Potential or Kinetic Energy.

EnergyPotential Energy is stored energy due to:

• Chemical Composition• Mass and Position• Elasticity

EnergyGravitational Potential Energy depends on an object’s mass, height and acceleration due to gravity.

Ug = mgh

Energy

What is the gravitational potential energy of a 57 kg rock on a 125 m hill?

EnergyElastic Potential Energy is energy stored in an object that is stretched or compressed.

EnergyWhat is the elastic potential energy of a spring that has been compressed 0.22 meters with a force of 3.5N?

3.5N

0.22m

Energy

Kinetic Energy is energy of motion. It depends on an object’s mass and velocity.

KE = ½ mv2

EnergyWhat is the kinetic energy of a 800Kg bobsled moving at 15 m/s?

         

EnergyBackyard Examples of Work and Energy (Problems w/ Calculations)http://www.youtube.com/watch?v=oyPOCSEJWP4         

EnergyLaw of Conservation

of Energy

The total amount of energy in a system is conserved. [Energy can neither be created nor destroyed, only changed forms].

Conservation of Energy

Lego – PE, KE and Energy Conservationhttp://www.youtube.com/watch?v=ZEajHxTM1CE&feature=related Divershttp://www.youtube.com/watch?v=KqQ83CPH3i8

EnergyUsually named for the source of the force involved.Mechanical Nuclear

Chemical Electromagnetic

Thermal (incl. electricity & magnetism)

Into to Types of Energy

http://www.youtube.com/watch?v=z7lCkQV7GEE&feature=related

 

EnergyMechanical Energy – Application of a force by the movement of objects or particles.

EnergyChemical Energy – Contained within the chemical bonds of molecules.

EnergyElectromagnetic Energy – Energy that travels as waves.

Electromagnetic EnergyElectricity – Force applied by electrons.

Electromagnetic EnergyMagnetism – Force applied by magnetic field.

Electromagnetic EnergyElectricity and Magnetism are related.

EnergyNuclear Energy – Energy contained within the nucleus of an atom.

Fission Fusion

Splitting the atom. Combining Nuclei

Nuclear Fusion

EnergyThermal Energy – The total internal energy of a substance. Dictates the amount of particle motion.

EnergyRemember: Energy can change forms.

Ex. Mechanical Electrical

Energy Conversions• What type of energy operates the toy

duck?• Describe the energy transformations

that gave the duck its energy.

Energy Resources• Non-Renewable – Sources that take

extremely long periods to develop– Fossil Fuels– Uranium

• Renewable (AKA Alternative) – Sources that can be easily replenished.– Solar– Wind– Hydroelectric– Geothermal– Biomass– Fuel Cells

Non-Renewable Energy Resources

Fossil Fuels – Derived from decayed organic matter.

[ Coal, Oil, Natural Gas ]

Non-Renewable Energy Resources

Non-Renewable Energy Resources

Nuclear - Radioactive elements that emit thermal energy upon decay.

Renewable Energy SourcesSolar – Energy converted from electromagnetic energy to electricity of thermal energy.

Thermal Collector Photovoltaic Cell

Renewable Energy SourcesSolar Arrays

Renewable Energy SourcesWind – Mechanical Energy derived from the

kinetic energy of moving air particles.

Renewable Energy SourcesHydroelectric - Mechanical Energy derived from the kinetic energy of moving water particles.

Renewable Energy Sources

Hydroelectric

Renewable Energy SourcesGeothermal – Using thermal energy from the

Earth.

Renewable Energy SourcesGeothermal – Using thermal energy from the

Earth.

Renewable Energy SourcesBiomass - Using the energy stored in organic matter to generate other forms of energy.

Renewable Energy SourcesFuel Cells – Electricity generated by forcing

hydrogen through a charged membrane.

Fuel Cell Animationshttp://www.upsaps.com/index.php?categoryID=146http://www.youtube.com/watch?v=_MsG9REFN3s

Renewable Energy SourcesFuel Cell Automobile

Renewable vs. Non-Renewable Energy Resources

Considerations :• Cost / Benefit• Availability /

Sustainability

Energy• New Energy

Source