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Forces Motion and Energy
Book M
Energy and Energy Resources
Chapter 5
Name _______________________
Class________________________
Test Date __Friday, May 30th 2014 ____
Chapter 5 Energy and Energy Resources
BMC5
Section 1 What Is Energy (124 – 131)
I.
Energy and Work: Working Together
*Energy is the ability to do ___work___. Work is done when a ____force__ causes an
object to move in the direction of the force. (unbalanced forces cause motion)
II.
Kinetic Energy
Kinetic energy is the energy of _____motion___. All moving objects have
____kinetic____energy.
A.
Kinetic Energy Depends on Mass and Speed
*Kinetic energy = mv2 / 2 *page 125 in the book!
III.
IV.
(kg●m2/s2 = Joules)
Potential Energy
*Potential energy is the energy an object has because of its ___position___.
A.
Gravitational Potential Energy
*When you lift an object, you do ____work___ on it. You transfer energy to the object
and give it _gravitational_____potential energy.
B.
Calculating Gravitational Potential Energy
gravitational potential energy = weight x height
Mechanical Energy
*Mechanical energy is the total energy of __motion___and the position of an object.
A.
Mechanical Energy of a Juggler’s Pin p. 127
V.
Other Forms of Energy
A.
Thermal Energy (measured with a THERMOMETER!)
*Thermal energy is all of the _____kinetic___energy due to the motion of the particles
that make up the object.
Particles move faster at higher temperatures so they have higher kinetic and thermal
energy.
Thermal energy also depends on the number of particles. Water versus steam:
ice cubes= particles tightly packed together, steam = particles very far apart!
B.
Chemical Energy
Chemical energy is potential energy that changes as its atoms are rearranged.
C.
Electrical Energy
*___Electrical______ energy is the energy of moving electrons.
D.
Sound Energy
*Sound energy is caused by an object’s ____vibrations______. When a guitar string
vibrates, it transfers some of its kinetic energy to the air. The air particles vibrate and
transmit some of the energy to your ears.
E.
Light Energy
*__Light____energy is produced by the vibrations of electrically charged particles.
F.
Nuclear Energy
Nuclear energy comes from changes in the nucleus of an atom.
Section 2 Energy Conversions p. 132 - 137
*Energy conversion is a change from one form of energy to another.*
I.
Kinetic Energy and Potential Energy
When a skier is at the top of the hill the skier’s __potential_____ energy is at a maximum. When
the skier is at the bottom of the hill the ___kinetic______ energy is at a maximum.
G.
VI.
Conversions involving Chemical Energy
*Chemical energy comes from the __food____ you eat.
A.
VII.
(kinetic + thermal)
Energy Conversions in plants
*____Photosynthesis___________ uses light energy to make new substances that have
chemical energy.
Why Energy Conversions Are Important
A.
VIII.
Elastic Potential Energy
A stretched rubber band stores potential energy.
Conversions Involving Electrical Energy
*We use electrical energy all of the time. When we use a light bulb, electrical energy is
converted into ___light___ energy and __thermal___ energy.
Energy and Machines
A.
Machines as Energy Converters
*Machines help us use energy by converting to the type that we need. A
_radiometer________ is a device that measures energy from the sun. p. 137
Section 3 Conservation of Energy
Pages 138 - 141
I.
Where does Energy Go?
Friction is a force that opposes motion between two surfaces that are touching.
*__Energy_______ must be used to overcome friction.
IX.
Energy is Conserved Within a Closed System
*In a roller coaster the _potential____ Energy (PE) is the greatest at the top of the first hill.
If you add together the car’s kinetic energy, and the thermal energy from friction, and the sound
energy you end up with the same total amount of energy as the original potential energy.
A.
Law of Conservation of Energy
*The Law of Conservation of Energy states that energy cannot be __created___ or
___destroyed____ but can be changed from one form to another.
In a closed system, all of the different forms of energy add up to the same total amount
of energy.
X.
No Conversion without Thermal Energy
*Any time energy is converted from one form to another form, some of the energy is converted
to _______thermal_____ energy.
A.
Perpetual Motion? No Way!
Perpetual motion machines are impossible because some waste thermal energy is
always created by energy conversions.
B.
Making Conversions Efficient
*Energy efficiency_____ is a comparison of the amount of energy before a conversion to
the amount of usable energy after a conversion.
Section 4 Energy Resources p. 142 - 147
I.
II.
III.
Nonrenewable Resources
*Fossil fuels are the most important ____nonrenewable______resource. Nonrenewable
resources include oil, natural gas, and coal.
A.
Uses of fossil fuels
Heat, generate electricity, gasoline, wax, and plastics are some of the uses.
B.
Electrical energy from fossil fuels
Electrical generators convert chemical energy in fossil fuels to electrical energy. Fuels
are burned to create thermal energy. The thermal energy is converted to kinetic energy
when steam pushes against turbine blades. The turbine spins a generator which
converts kinetic energy into electrical energy.
C.
Nuclear Energy
Renewable Resources
Renewable resources are natural resources that can be replaced as fast as they are being
consumed. Solar and wind energy are considered to be practically limitless.
A.
Solar Energy
Energy from the sun.
B.
Energy from Water
*Turbines turned by water are connected to a __generator____ that changes kinetic
energy into electrical energy.
C.
Wind Energy
*A wind ___turbine_____ changes the kinetic energy of the air into electrical energy by
turning a generator.
D.
Geothermal Energy
E.
Biomass
The Two Sides to Energy Resources
There are advantages and disadvantages to all types of energy resources
A.
Choosing the Right Energy Resource
Energy planning in all parts of the world requires careful consideration of energy needs
and the availability and responsible use of resources.