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Energy and energy
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Section 1
What is Energy?
Energy is the ability to do work.
 Work is when a force causes an object to
move in the direction of the force
 Work and energy are both expressed in
joules
Kinetic energy
 The energy of motion.
 If it moves it has kinetic energy.
 Kinetic energy can be calculated using
mass and velocity
 KE=mv2/2
 Example If a car with a mass of 2000kg is
traveling at 30 m/s what is it’s KE?
 {2000 x (30 x 30) } / 2 = 900,000 joules
Potential energy

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The energy of position
Depends on weight and height
GPE=weight (in Newtons) X height (in meters)
Example- the 10 N rock is balanced on the top
of the 1400 m hill. What is it’s gravitational
potential energy?
 GPE = 10 N X 1400 m = 14,000 joules
http://science.howstuffworks.com/engineering/stru
ctural/roller-coaster3.htm
http://www.science-animations.com/supportfiles/energy.swf
Mechanical energy
 Is the combination of potential and kinetic
energy
 Because the two energies are closely
related.
 ME= GPE+KE
http://www.physicsclassroom.com/mmedia/e
nergy/se.cfm
Other types of energy
 Thermal – All of the atoms in things move, this
molecular movement is measured by
temperature. Boiling water takes thermal
energy.
http://www.nd.edu/~ysun/Yang/PhysicsAnimatio
n/collection/transportP.swf
 Chemical- Energy can be stored in the bonds
between atoms, when you break these bonds to
rearrange the atoms you can release the energy.
Digesting food releases chemical energy
( possible in the dark lifesavers activity)
Other types of energy
 Electrical- when the electrons in a wire ( or other
substance) move back and forth.
 Sound- is the movement and vibrations of
particles in the air, usually caused by movement.
( needs particles to work, there is no sound in
space, so a space ship blowing up would
actually be silent)
 Light- the vibrations of electrically charged
particles. ( does not need atom particles to work
so you would see the blast in space!)
Other types of energy
 Nuclear- Energy created by changing the
nucleus of an atom. There are two types…
Fission - which is taking a big atom and
breaking it apart ( power plants
like
Cordova do this)
Fusion- combining small atoms. (The
sun takes the small atoms of
hydrogen and fuses them to make
helium.)
Section 2
Energy Conversions