Energy. The ability to do work and overcome resistance. The ability to cause change.
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Transcript of Energy. The ability to do work and overcome resistance. The ability to cause change.
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
