Transcript energy - My eCoach

ENERGY
ENERGY CHART
Definition
WORK
POWER
ENERGY
Transfer of
energy
Rate in which energy
is being transferred
The ability to do work
Calculation Formula
Kinetic energy =
½ X Mass X Velosity²
Force X Distance
Energy transferred
Time
Gravitational Potential
Energy =
Weight X Height
Units of Measure
Newton meters
Watts
Joule
Symbol
N·m
W
J
WORK:
• When a force moves an
object through a distance.
• The transfer of energy.
POWER
•The rate in which
energy is transferred
•The amount of energy
transferred in a unit of
time
ENERGY
•The ability to do work
•Anytime work is being
done on an object it
gains energy.
VELOCITY
•Speed and direction of
an object
newton
• The newton is the unit of force
derived in the SI system
• It is equal to the amount of force
required to give a mass of one
kilogram an acceleration of one
meter per second squared.
• Newton = Mass (kg) X the
acceleration of gravity (9.8)
KINETIC ENERGY
• Energy of motion
• Increases as the mass
increases
• Increases as the velocity
increases
POTENTIAL ENERGY
•Stored energy
•Held in readiness
•Has the potential of
doing work
Calculating Potential Energy
Gravitational Potential Energy is the
Potential Energy related to an
objects height.
Gravitational Potential Energy = Weight X Height
Elastic Potential Energy
• Potential Energy
associated with objects
that can be stretched.
• Example: An archer
readying his bow and
arrow.
CONVERTING MASS (kg) to
newtons
The average cell phone weighs .100 kg. How much
does it weigh in newtons?
MASS (kg) X 9.8 = newtons
.100 kg X 9.8 = .98n
YOU TRY…
An object has a mass
of 3.8 kg. How much
force does it have?
MASS (kg) x 9.8 (gravitational force)
3.8 kg X 9.8 (gravitational force)
37.24n
CALCULATING
KENETIC ENERGY
Kinetic Energy =
½ X Mass X Velocity²
An object has a mass of 5.7 kg is
moving at 3.5 m/s. What is its
KENETIC ENERGY?
• KE = ½ X MASS X VELOCITY²
• KE= ½ X (5.7 kg X 9.8) X (3.5 X 3.5)
• KE = ½ X 55.89 n X (3.5 X 3.5)
• KE = ½ X 55.89 n X 12.25
• KE = 342.32 J
YOU TRY…
An object with a mass of 11.12 kg is
moving at 5.5 m/s. How much
kinetic energy does it have?
KE = ½ X MASS (n) X Velocity²
KE= ½ X (11.12kg X 9.8) X 5.5²
KE = ½ X 108.97n X 5.5²
KE = ½ X 108.97 n X 30.25 m/s²
KE = 1648.17 J
Potential Energy
An object weighs 50 n and is sitting on a shelf
3.5 meters from the floor. What is its
potential energy?
PE = W X H
PE = 50 n X 3.5
PE = 175 J
YOU TRY…
An object is sitting on a brick wall at the
height of 5.8 m. The mass of the object is
10.3kg. What is its POTENTIAL ENERGY?
DID YOU REMEMBER TO CONVERT kg to n?
PE = W X H
PE = 100.94 n X 5.8 m
PE = 585.45 J
INSTRUCTIONS #1:
• Fold a piece of paper in half 3
times hamburger style.
• Draw a roller coaster
• Number each area where the
fold meets the coaster lines.
INSTRUCTIONS #2
Make the chart below in your folder
Kinetic
1
2
3
4
5
6
7
Potential
At each number describe whether
the roller coasters KINETIC ENERGY
is increasing or decreasing.
Describe weather the potential
energy is increasing or decreasing.
EXAMPLE #1
The average cell phone weighs .100 kg. How much
does it weigh in newtons?
Kinetic Energy =½ X .100 kg X 9.8 (force of gravity)
Kinetic Energy = ½ X .98n
Kenetic Energy =
EXAMPLE
Wile E. Coyote is
attempting to push a
50000 kg safe on the
roadrunner below. How
much KENETIC ENERGY
will the street absorb?
USING THE FORMULA
Kinetic Energy = ½ X Mass X Velocity ²
½ X 50000 kg X 9.8²
½ X 50000 kg X (9.8 X 9.8)
½ X 50000 kg X 96.04ms/s
2401000.0 n
CALCULATE WORK
newton:
• unit of force based on the metric system
• It is the force that produces an
acceleration of 1 meter per second per
second when exerted on a mass of 1
kilogram.
• The newton is named for Sir Isaac
Newton.
JOULE
• One joule is the work
done, or energy expended.
• Can also be called a
newton meter
FORMS OF
ENERGY
MECHANICAL ENERGY
• Associated with the position and motion
of an object.
• Objects in motion have mechanical energy
only. ( A car racing down the road)
• Objects can have gravitational potential
energy only. (A trophy sitting on the shelf)
• Sometimes objects can have both. (A
football being thrown)
MECHANICAL
ENERGY
+ / OR
KINETIC
ENERGY
POTENTIAL
ENERGY
KENETIC
ENERGY
Gravitational
Potential
Energy
MECHANICAL ENERGY =
Potential Energy +
Kinetic Energy
FORMS OF ENERGY
THAT INVOLVE THE
MOVEMENT OF
PARTICLES TO SMALL
TO SEE.
THERMAL ENERGY
ALL OBJECTS ARE MADE UP OF
PARTICLES CALLED ATOMS AND
MOLECULES.
ATOMS ARE IN CONSTANT
MOTION, THEREFORE, THE
FASTER THEY MOVE, THE
MORE KINETIC ENERGY
THEY HAVE.
THERMAL
ENERGY IS THE
TOTAL
POTENTIAL AND
KINETIC ENERGY
OF THE
PARTICLES IN
AN OBJECT.
ELECTRICAL ENERGY
• ENERGY OF ELECTRICAL
CHARGES
• Lightning has Kinetic Energy
• Batteries have Potential
Energy
CHEMICAL ENERGY
• Chemical compounds are objects
made up of two or more elements.
–Salt ( Sodium + Chlorine)
–Carbon Dioxide (Carbon + Oxygen)
• Chemical energy hold these bonds
together
• Chemical energy is stored in foods
we eat, matches and cells in your
body.
• When the bonds in the chemical
compounds break, new chemical
compounds may form and chemical
energy may be released.
NUCLEAR ENERGY
•Potential Energy
because it is stored in
the NUCLEUS of the
atom
• Nuclear energy is released
during a nuclear reaction
–Nuclear fission occurs when the
nucleus splits. Used in power plants to
make electricity.
–Nuclear Fusion occurs when the nuclei
of atoms join together. Occurs in the
sun.
ELECTROMAGNETIC ENERGY
•Example: Sunlight
•Travel in waves
•Have properties of both
electrical properties and
magnetic properties.
ENERGY
TRANSFORMATION
and CONSERVATION
ENERGY
TRANSFORMATION
• A change from one form of
energy to another.
• Most forms of energy can
be transformed into other
forms.
SINGLE TRANFORMATION
• Changing one form of energy to another.
• Toaster takes electrical energy and transfers
it to thermal energy.
• As we eat food, chemical energy from the
food is transferred to mechanical energy for
us to do work.
• Electrical energy from the batteries inside
our cell phones is transferred to
electromagnetic energy for communication
MULTIPLE TRANSFORMATION
MECANICAL ENERGY TO THERMAL
ENERGY
THERMAL
ENERGY CAUSES
A THE PARTICLES
IN THE MATCH TO
RELEASE THE
STORED
CHEMICAL
ENERGY
(phosphorous and
a chlorate mix)
Chemical
energy is turned
into
Electromagnetic
energy (light)
TRANSFORMATIONS
BETWEEN
POTENTIAL AND
KINETIC ENERGY
Highest potential
Energy, no kinetic
Energy
Potential
Energy
increases,
Kinetic
Energy
decreases
Kinetic
Energy
increases,
no potential
energy
GREATEST
POTENTIAL
ENERGY
GREATEST
POTENTIAL
ENERGY
Greatest Kinetic
Energy, No
Potential Energy
KINETIC ENERGY
KINETIC
ENERGY
to
ELASTIC
ENERGY
ELASTIC ENERGY TO
POTENTIAL ENERGY
POTENTIAL ENERGY TO
KINETIC ENERGY
LAW of CONSERVATION of
ENERGY
Energy cannot
be created nor
destroyed
ENERGY AND FRICTION
• Friction transfers mechanical
energy to thermal energy
• No machine is 100% effective
because some of its energy is
transferred into thermal
energy.
ENERGY AND MATTER
• Albert Einstein's theory of
relativity states that energy can
sometimes be created by
destroying matter.
• By destroying just a small
amount of matter releases huge
amounts of energy.
THE
TRANSFER
OF HEAT
THERMAL ENERGY
• The total energy of all particles
in an object
• The more particles an object has
at a given temperature the more
thermal energy it has.
• The higher the temperature, the
higher the thermal energy it has.
HEAT
•The transfer of thermal
energy from matter at
higher temperatures to
matter at a lower
temperature.
http://www.learn360.com/ShowVideo.aspx
?TagName=conduction&ID=34162
Three ways heat can
move
•Conduction
•Radiation
•Convection
CONDUCTION
• Transfer of heat from one particle of matter to
another part without the movement of
matter.
CONVECTION
• Transfer of heat through a
current within a fluid.
• Convection currents are when
warm air rises and the cool air
flows into its place.
RADIATION
•Transfer of energy by
electromagnet waves.
•Does not need matter
to transfer heat.
HEAT FLOW
• Heat flows from a warm object to a
cooler object
• When heat flows into matter, the
thermal energy and the temperature of
the matter increases.
• At the same time, the temperature of
the matter loosing the heat decreases.
HOW DOES ICE CREAM
GETS COLD?
1) The ingredients in the
ice cream (milk and
sugar) is not as cold
as the ice cream itself.
2) Within the ice cream
maker, a metal can
packed with ice is
used.
3) Ingredients turn
colder because its
thermal energy
transfers to the colder
ice filled can.
CONDUCTORS
• Materials that
transfer energy
well
• Depends of the
density and how
the particles are
arranged.
INSULATORS
• Materials that do not
conduct heat well
• Examples: Wood,
straw, wool and
gasses.
• Clothes are not good
conductors because
they prevent the
transfer of thermal
energy.
ENERGY
and FOSSIL
FUELS
FORMATION of FOSSIL FUELS
• Fuel is a material that contains
potential energy
• Some fuels used today are made
from materials that formed
hundreds of million years ago.
• Coal, petrolium and natural
gasses are known as fossil fuels
FORMATION OF COAL
• Over time, plants and animals died
• Remains piled up in thick swamps
and marshes
• Clay and sand covered them causing
great pressures and temperatures
• Coal is formed
ENERGY FROM THE SUN
• Fuels do not create energy
• Fossil Fuels contain energy that came
from the Sun.
• Suns electromagnetic energy transforms
living things into chemical energy.
• As these animals and plants died their,
chemical energy was trapped in the coal.
Use of Fossil Fuels
• Fossil fuels can be burned to release
the chemical energy.
• The process of burning fuels is
known as combustion
• Combustion is the transfer of energy
from chemical energy to thermal
energy.
USING FOSSIL FUELS
Sun transforms
nuclear energy
to electromagnet
energy
Ancient plants and animals transform
electromagnet energy from the sun to
stored energy. Their remains are coal.
Coal is burned to make steam,
transforming stored chemical
energy to thermal energy
The steam turns turbines,
transforming thermal energy
to mechanical energy.
The turbines
spin electric
generators,
transforming
mechanical
energy to
electrical
energy
Your hair dryer transforms
electrical energy to thermal
energy
GRADE TIME (due today): Take EVERYTHING out of
your notebooks
Look for:
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NOTES: What is Energy? (pg 442 – 446)
Section 1 Assessment page 446
NOTES: Forms of Energy (pg 447 – 451)
Section 2 Assessment page 451
NOTES: Energy Transformation Conservation (454 – 459)
Section 3 Assessment
NOTES: Transfer of Heat ( pg 479 – 483)
Section 4 Assessment page 495
NOTES: Energy and Fossil Fuels (pg 462 – 465)
Section 4 Assessment page 465
Workbook pages 265 - 278