Transcript Pwrpt - Energy

Energy
Energy
• The ability to
do work and
overcome
resistance.
• The ability to
cause
change.
Energy
Work – The relationship
between force on an object
and distance moved.
W = Fd
Work = Force · Distance
Energy
Unit 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 Joule
1818 -1889
Work – Energy Theorem
W = ∆ EK
Energy
Energy is Classified as either
Potential or Kinetic Energy.
Energy
Potential Energy is stored
energy due to:
• Chemical Composition
• Mass and Position
• Elasticity
Energy
Gravitational 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?
Energy
Elastic Potential Energy is energy
stored in an object that is stretched
or compressed.
Energy
What 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
2
mv
Energy
What is the
kinetic energy
of a 800Kg
bobsled
moving at 15
m/s?
Energy
Backyard Examples of Work and Energy
(Problems w/ Calculations)
http://www.youtube.com/watch?v=oyPOCSEJWP4
Energy
Law 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 Conservation
http://www.youtube.com/watch?v=ZEajHxTM1CE&feature=related
Divers
http://www.youtube.com/watch?v=KqQ83CPH3i8
Energy
Usually named for the source of
the force involved.
Mechanical
Chemical
Thermal
Nuclear
Electromagnetic
(incl. electricity & magnetism)
Into to Types of Energy
http://www.youtube.com/watch?v=z7lCkQV7GEE&feature=related
Energy
Mechanical Energy –
Application of a force by the
movement of objects or
particles.
Energy
Chemical Energy – Contained
within the chemical bonds of
molecules.
Energy
Electromagnetic Energy –
Energy that travels as waves.
Electromagnetic Energy
Electricity – Force applied by
electrons.
Electromagnetic Energy
Magnetism – Force applied by
magnetic field.
Electromagnetic Energy
Electricity and Magnetism are
related.
Energy
Nuclear Energy – Energy contained
within the nucleus of an atom.
Fission
Splitting the atom.
Fusion
Combining Nuclei
Nuclear Fusion
Energy
Thermal Energy – The total
internal energy of a substance.
Dictates the amount of particle
motion.
Energy
Remember: 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 Sources
Solar – Energy converted from electromagnetic
energy to electricity of thermal energy.
Thermal Collector
Photovoltaic Cell
Renewable Energy Sources
Solar Arrays
Renewable Energy Sources
Wind – Mechanical Energy derived from the
kinetic energy of moving air particles.
Renewable Energy Sources
Hydroelectric - Mechanical Energy derived
from the kinetic energy of moving water particles.
Renewable Energy Sources
Hydroelectric
Renewable Energy Sources
Geothermal – Using thermal energy from
the Earth.
Renewable Energy Sources
Geothermal – Using thermal energy from
the Earth.
Renewable Energy Sources
Biomass -
Using the energy stored in
organic matter to generate other forms of
energy.
Renewable Energy Sources
Fuel Cells – Electricity generated by forcing
hydrogen through a charged membrane.
Fuel Cell Animations
http://www.upsaps.com/index.php?categoryID=146
http://www.youtube.com/watch?v=_MsG9REFN3s
Renewable Energy Sources
Fuel Cell Automobile
Renewable vs. Non-Renewable
Energy Resources
Considerations :
• Cost / Benefit
• Availability /
Sustainability
Energy
• New Energy
Source