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Energy and Energy
Resources
What Is Energy (chapter 5 section 1)
Energy Conversions ( Chapter 5 sec 2)
What is Energy?
 Energy is the ability to do work
 Work occurs when a force is applied to an object in
the same direction that the object moves
 Energy is transferred from one object to another
Kinetic Energy
 Kinetic energy(KE) is the energy of motion
 All moving objects have kinetic energy
 The amount of kinetic energy that an object has can
be calculated by the following formula:
 KE= mv2/2 (m = mass v = velocity or speed)
 The more mass an object has, the more kinetic energy
it has
 The faster an object is moving, the more kinetic energy
Potential Energy
 Potential energy is the energy that an object has because
of its position; it is STORED ENERGY (has the potential
to do work)
 Gravitational Potential Energy (GPE)
 Elastic Potential Energy
Gravitational Potential
Energy
 Gravitational Potential Energy is energy that is
stored due to the gravitational attraction of the
Earth on the object
 When an object is lifted up off of the ground, a force is
applied to lift the object. The energy used to lift the
object is stored in the object
 GPE is calculated with the formula
 GPE = Weight X height
 Units = Joules ( newton/meters)
Elastic Potential Energy
 Energy stored as a result of the deformation
(changing the shape) of an elastic object
 Examples:
 Stretching a spring
 Stretching an elastic band
Mechanical Energy
 Mechanical Energy (ME) is the total energy of
kinetic(KE)and potential energy (PE)
 ME = KE + PE
 As KE increases, PE decreases
 As KE decreases, PE increases
Kinetic and Potential
Energy Video
 The Story of Kinetic and Potential Energy
Other Forms of Energy
(most can exist as potential and kinetic forms)
 Thermal energy – the energy that exists due to the
kinetic energy of moving atoms that make up the
matter
Other Forms of Energy
(most can exist as potential and kinetic forms)
 Chemical energy – the energy that comes from the
rearrangement arrangement of atoms
 Food energy is a type of chemical energy
 Electrical energy – the energy of moving electrons
Other Forms of Energy
(most can exist as potential and kinetic forms)
 Sound energy – the energy caused by an objects vibration;
travels in waves
 Must have a medium (matter) to travel
 Light (radiant) energy – the energy produced by the vibration
of electrically charged particles; exists as a wave and a particle
 Does not need a medium to travel; can travel in a
vacuum(where the is no matter)
Other Forms of Energy
(most can exist as potential and kinetic forms)
 Nuclear energy – the energy that comes from changes
in the nucleus of an atom
 Fusion – the joining of nuclei
 Fission – the splitting of nuclei
The Seven Forms of Energy
Video Clip
All forms of energy can change
(convert) into other forms of energy
 Energy conversion is a change from one form of
energy to another
Examples of energy
conversions
 Potential to kinetic
 Kinetic to potential
Examples of energy
conversions
 Food energy(chemical) to mechanical or kinetic
energy ( cereal for breakfast used to allow you to
move)
Conversions Involving
Chemical Energy In Plants
Why Energy Conversions
Are Important
 Energy conversions are needed for everything we
do
 Without energy conversions we could not live or do
all the things we do
 Machines can make work easier by converting
energy into the form of energy needed to do the
work.
 Not all energy conversions are useful for the work
that you are trying to do – some is “wasted” energy
Energy and Machines