ENERGY

ENERGY CHARTWORK POWER ENERGY

Definition Transfer of energy

Rate in which energy is being transferred

The ability to do work

Calculation Formula

Force X Distance Energy transferred

Time

Kinetic energy =½ X Mass X Velosity²

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 EnergyGravitational 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 Velocity²KE= ½ X (11.12kg X 9.8) X 5.5²

KE = ½ X 108.97n X 5.5²KE = ½ X 108.97 n X 30.25 m/s²

KE = 1648.17 J

Potential EnergyAn object weighs 50 n and is sitting on a shelf 3.5 meters from the floor. What is its potential energy?

PE = W X HPE = 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 HPE = 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 #2Make the chart below in your folder

Kinetic Potential1234567

At each number describe whether the roller coasters KINETIC ENERGY

is increasing or decreasing. Describe weather the potential

energy is increasing or decreasing.

EXAMPLE #1The 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 =

EXAMPLEWile E. Coyote is attempting to push a 50000 kg safe on the roadrunner below. How much KENETIC ENERGY will the street absorb?

USING THE FORMULAKinetic Energy = ½ X Mass X Velocity ²

½ X 50000 kg X 9.8²½ X 50000 kg X (9.8 X 9.8)½ X 50000 kg X 96.04ms/s

2401000.0 n

CALCULATE WORKnewton: • 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

KINETICENERGY

POTENTIALENERGY

+ / OR

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 ENERGYALL 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 TRANSFORMATIO

N 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

Potential Energy increases, Kinetic Energy decreases

Highest potential Energy, no kinetic Energy

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:– 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