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Chapter 15
Page 446-467
Chapter 15 Section 1
Pg. 446-452
Energy and Work
• Work- done when a _____ moves an object
through a distance, a transfer of energy
– Measured in joules (J)
• Energy- the _______ to do work
– It is known by the changes it causes
– Examples are sound and motion
– Measured in ______ (J)
• 1 joule = 1 newton-meter
• When work is done on an object, energy is
transferred to that object
Kinetic Energy
• Kinetic Energy- the energy of _______
– Comes from the Greek work kinetos, meaning
“______”
– The kinetic energy of any moving object depends
upon its ____ and speed.
Math Practice
• Page 448
Potential Energy
• Potential Energy- energy that is ______ as a
result of position or shape
– Stored ______ gets converted into kinetic energy
– You can store energy just by picking up a book and
holding it. Let go, and that stored energy will turn
into the ______energy of motion
Gravitational Potential Energy
• Gravitational Potential Energy- ________
energy that depends upon an object’s height
– The PE __________ when an object is raised to a
higher level
– Depends on an object’s mass, ______, and
acceleration due to gravity (9.8 m/s2)
Elastic Potential Energy
• Elastic Potential Energy- PE of an object that
is __________ or compressed
– Said to be elastic if it springs back to its original
shape after it is stretched or __________
– Can also be stored in objects that are compressed,
such as _______
– Broken rubber band: it’s elastic PE is converted
into _______ energy
Forms of Energy
• All ______ can be considered to be
kinetic energy, potential energy, or
the energy in fields such as those
produced by ____________ waves
– Ex: fireworks, nuclear energy, lightning bolts, etc.
• The major forms of energy are mechanical
energy, ________ energy, chemical energy,
electrical energy, electromagnetic energy,
and nuclear energy
Mechanical Energy
• Mechanical Energy- the energy associated with
the _______ and position of everyday objects
– Not limited to machines
– The sum of an object’s _______ energy and kinetic
energy
Mechanical Energy = KE + PE
– Ex: speeding trains, bouncing balls, sprinting athletes
• Does NOT include thermal, chemical or other energy
associated with the motion or arrangement of atoms or
molecules
Thermal Energy
• Thermal Energy- the total potential and
kinetic energy of all the __________ particles
in an object
• When an object’s _______ move faster, its
thermal energy increases and the object
becomes ________
Chemical Energy
• Chemical Energy- the energy ______ in
chemical bonds
– When bonds are broken, the ______ energy can
do work
– Example: wood burning, when gasoline is burned
Electrical Energy
• Electrical Energy- the energy associated with
electric _______
– Electric charges can exert _____ that do work
– Example: batteries
Electromagnetic Energy
• Electromagnetic Energy- a form of ______
that travels through _____ in the form of
waves
– Radiated by the sun
– Examples: visible light, X-rays
Nuclear Energy
• Nuclear Energy- the energy stored in ______
nuclei
– Examples: nuclear ______ (is a process that
releases energy by splitting nuclei apart) and
nuclear ______ (releases energy when less
massive nuclei combine to form a more massive
nucleus)
Chapter 15 Section 2
Page 453-459
Energy Conversion
• Energy can be ________ from one form to
another, known as energy conversion
• Examples:
– Wind-up toys: store elastic PE in spring, when
released the ___ is converted to KE and the toy
moves
– Light bulbs: convert _______ energy to thermal
and electromagnetic energy
– See more on page 454 of book
Conservation of Energy
• The law of conservation of energy states that
energy ______ be created or destroyed
– Energy can be converted from one form to
_______
– In a closed system, the amount of ______ present
at the beginning of a process is the same as the
amount of energy at the end
– See example on page 455
Energy Conversions
• ___________ potential energy of an object is
converted to the kinetic energy of ______ as
the object falls
• Conversions between KE and PE can happen in
_____ directions
Energy Conversion in Pendulums
• Rope swing is an example of a _________.
– Pendulum consists of a weight swinging back and
forth from a ______ or string
– KE and PE undergo constant conversion as a
pendulum swings.
– At HIGHEST point in swing, pendulum is
momentarily ___________: the weight at the end
has zero KE and maximum PE
– As is swings ________, PE is converted to KE
– At the _______ of the swing, the pendulum has
maximum KE and zero PE
Energy Conversion in the Pole Vault
• Pole-vaulter’s KE is _______ converted into
elastic PE as the pole bends. It ______ back
into shape, propelling the pole-vaulter upward
– As he soars KE _________ while he gains
gravitational PE
– At the ________ point, gravitational PE begins to
convert back to KE
Energy Conversion Calculations
• Conservation of Mechanical Energy
– When _______ is small enough to be _______
• Math Practice pg. 458
Energy and Mass
• Einstein (1879-1955)
– Developed theory of ________
• E = mc2
(Energy = mass X c-the speed of light squared)
• Einstein’s equation, E =mc2 says that energy
and mass are _________ and can be
converted into each other
– In other words: _______ is released as matter is
destroyed, and matter can be _______ from
energy
Energy and Mass
• In nuclear _______ and fusion reactions, large
amounts of energy are released by the
destruction of very _____ amounts of matter.
• The law of conservation of energy has been
modified to say that ____ and energy
together are always conserved
Chapter 15 Section 3
Page 462-466
Nonrenewable Energy Resources
• Nonrenewable energy resources- exist in
______ quantities, once used, cannot be
replaced except over the course of millions of
years
• Examples: oil, natural gas, ____, and uranium
• _______ fuels: oil, natural gas, and coal
– Creates pollution
• Many of these resources are being used _____
than they can be replaced
Nonrenewable Energy Resources
Renewable Energy Resources
• Renewable energy resources- resources that
can be _______ in a relatively short period of
time
– Most _________ directly/indirectly from the sun
– Example: hydroelectric, solar, geothermal, wind,
biomass
– Challenge is to find ________ ways to make these
energy resources inexpensive and convenient
Renewable Energy Resources
Hydroelectric Energy
• Hydroelectric energy- energy obtained from
_______ water
• As water flows ________, its gravitational PE
is converted into KE which can be used to turn
turbines that are _______ to electric
generators
• Many hydroelectric power ______ rely on
dams
– Cause a few environmental problems (fish
spawning)
Hydroelectric Energy
Solar Energy
• Solar energy- sunlight that is ________ into
usable energy
– nonpolluting
Geothermal Energy
• Geothermal energythermal energy ______
Earth’s surface
• Steam is used to drive
electric generators
• __________
• Not widely available
Other Renewable Resources
• Biomass energy- the ________ energy stored
in living things
– Can be _________ directly into thermal energy
(ex: wood burning)
• Hydrogen fuel cell- generates electricity by
reacting _________ with oxygen
– End product is water, nonpolluting
Renewable vs. Nonrenewable
Conserving Energy Resources
• Energy resources can be ________ by
reducing energy needs and by increasing the
efficiency of energy use
• Energy conservation- finding ways to use ___
energy or to use ________ more efficiently
– Turn of lights when not in use
– Energy efficient products (appliances, cars, light
bulbs)
Works Cited
Frank, Wysession, & Yancopoulos. “Chapter 15
Energy.” Physical Concepts in Action. Upper
Saddle River: Pearson, 2010. 446-467. Print.