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Energy
Chapter 15 Section 1
Vocabulary
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Energy- is the ability to do work
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Kinetic Energy- the energy of motion
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Potential Energy- energy that is stored as a result of position or shape
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Gravitational potential energy- potential energy that depends upon an object’s height
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Elastic potential energy- the potential energy of an object that is stretched or compressed
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Mechanical Energy- the energy associated with the motion and position of everyday objects
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Thermal Energy- The total potential & kinetic energy of all the microscopic in an objects
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Chemical Energy- the energy stored in chemical bonds
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Electrical Energy- The energy associated with electric charges
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Electromagnetic Energy- A form of energy that travels through space in the form of waves
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Nuclear Energy- Energy stored in atomic nuclei.
Key Points
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How is gravitational potential energy
determined?
An objects gravitational energy
depends on its mass, its height and the
acceleration due to gravity.
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What are the major forms of energy?
The major forms of energy are
mechanical energy, thermal energy,
chemical energy, electrical energy,
electromagnetic energy, and nuclear
energy
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How are energy and work related?
Energy and work are related
because work is a transfer of energy.
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What factors does the kinetic energy
of an object depend on?
The kinetic energy is any moving
object depends upon its mass and
speed.
Section 2
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Energy Conversion- is the process of changing
energy from one form to another.
Key Points
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Can energy be converted from one
form to another?
Energy can be converted to one
form to another.
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What is the law of conservation
energy?
The law of conservation energy
of energy states that energy cannot be
created nor destroyed.
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What energy conservation takes
place as an object falls towards
earth?
The gravitational potential
energy of an object is converted to the
kinetic energy of motion as the object
falls.
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How are energy and mass related?
Einstein’s equation E=mc squared
says that energy and mass are equivalent
and can be converted into each other.
Extra Key Points
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Mechanical energy is the sum of an object’s potential energy and kinetic energy.
All chemical compounds, including fuels such as coal and gasoline, store energy.
A nuclear power plant uses nuclear fission reactions to generate electricity.
Nuclear fission is a process that releases energy by splitting nuclei apart.
A second type of nuclear reaction, nuclear fusion, releases energy when less massive nuclei
combine to form a more massive nucleus.
Section 3
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Non renewable energy resources- exist in limited quantities and once used cannot be replaced
except over a course of million of years.
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Fossil fuels- oil, natural gas, and coal.
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Renewable energy resources- are resources that can be replaced in a relatively short period of
time
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Hydroelectric energy- energy obtained from flowing water
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Solar energy-sunlight that is converted into usable energy
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Geothermal energy- is thermal energy beneath earth surface
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Biomass energy- the chemical energy stored in living things
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Hydrogen fuel cell- generates electricity by reacting hydrogen with oxygen
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Energy conversion- finding ways to use less energy or to use energy more efficiently.
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What are the major nonrenewable and renewable sources
of energy?
The major nonrenewable resources are oil, natural
gas, coal and uranium. The major renewable resources are
hydroelectric, solar geothermal, wind, biomass, and possibly in
the future nuclear fusion.
Key points
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How can energy resources be conserved?
Energy resources can be conserved by reducing
energy needs and by increasing the efficiency of energy use.
Extra Vocabulary Chapter 15
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Kinetic Energy (KE): KE=1/2MV squared
KE=Joules; M=Mass in kilograms; V=Velocity in meters per second
Potential Energy (PE): PE=MGH
PE=Joules; M=Mass in kilograms; G=Gravity in 9.8m/s squared;
H=Height in meters
★ Conservation of Mechanical Energy (ME): ME=KE+PE
★ ME= Mechanical Energy in joules; PE=joules; KE=Joules
Einstein’s Equation E=MC squared
❏ Einstein’s Equation states that energy and mass are equivalent and CAN be
converted into each other.
❏ C=speed of light in meters/second; M=Mass in kilograms
Extra Key Points
➔ Mechanical energy is the sum of an object’s potential energy and kinetic
energy.
➔ All chemical compounds, including fuels such as coal and gasoline, store
energy.
➔ A nuclear power point uses nuclear fission reactions to generate electricity.
➔ Nuclear fission is a process that releases energy by splitting nuclei apart.
➔ A second type of nuclear reaction nuclear fusion, releases energy when less
massive combine to form a more massive nucleus.
➔ When energy changes from one form to another, the total energy remains
unchanged even though many energy conservations may occur.
Extra Key Points
★ When work is done on an object, energy is transferred to that object.
★ Mechanical energy does not include thermal energy, chemical energy, or other
forms of energy associated with the motion or the arrangement of atoms and
molecules.
★ The sun radiates electromagnetic energy into space and is the source, either
directly or indirectly of most of the world’s energy supplies.
Energy in Action