Transcript ENERGY power point

Energy
• Energy – The ability to do work.
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The sun is going to die!!
Oh No!!
(in 5,000,000,000 years)
Mechanical Energy
Total energy of motion and position of an
object.
 It can be all potential energy, all kinetic
energy, or some of both.
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Kinetic Energy
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The energy of motion
Potential Energy – The stored energy
that result from the position or shape of an
object.
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Elastic potential energy –The potential energy associated
with objects that can be compressed or stretched.
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Gravitational potential energy – Potential energy related
to an objects height. Weight x Height
There are 6 Forms of Energy
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1) Mechanical
a) Kinetic energy- energy of a moving object. ex.- rock rolling
down a hill.
kinetic energy = 1/2 mv2
example; a 20 kg goat ran at 3 m/s.
20kg x (3m/s) 2 = 20kg x 9 m/s2 = 180 = 90 J
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– b) Potential Energy- “possible” energy that an object has because
of its position-. ex- rock on top of a hill.
Potential energy= mass x gravity x height ( g=9.8 m/s/s)
Example: a 40 kg skateboarder is on a 2m ramp.
40 kg x 9.8 m/s/s x 2m = 784 J
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2) Chemical energy- Potential energy
stored in the chemical bonds that hold
molecules together. Chemical energy is
stored in food, fossil fuels (gasoline, oil,
coal), batteries, and wood and cells in our
bodies.
3) Electrical energy-
Energy of moving electrons. It
is often an “in- between” form between 2 other forms of
energy. Can be kinetic or potential
Examples- electric heater, blender.
power plant (burns coal) →→power lines→→→blender
(chemical- thermal)
(electrical)
(kinetic)
4) Electromagnetic ( or radiant) energy: The
energy of waves.
Red
orange, yellow,
green
blue
indigo
violet
Visible light is only 1/1000th of the electromagnetic
spectrum.
Thermal Energy
Thermal energy is the total potential and
kinetic energy of particles in an object.
(You should know about this already!)
6) Nuclear energy- Energy locked in atoms.
The energy can be released by splitting
atoms (known as fission- This happens in
nuclear power plants) or by combining
atoms (known as fusion- happens in the
sun and in nuclear bombs)
Fusion
Fission
Renewable vs. Nonrenewable energy
 Energy sources can be either 1) Renewable- The source is replenished
(comes back) quickly by natural
processes. Examples- wind, solar,
hydropower (dams), geothermal (heat
from underground), plants, trees (some),
cow dung.
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Non Renewable
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Energy Resources that cannot be replaced
after they are used or can be replaced
only over thousands or millions of years.
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Fossil fuels are the most important nonrenewable resources.
2) Nonrenewable- The source is used up
and it is not replaced.
 Examples -fossil fuels (coal, oil, gasoline),
uranium
(nuclear power source), trees
(some)
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