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
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
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
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.
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.
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)
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.
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 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
• 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
THERMAL ENERGY CAUSES A THE PARTICLES
IN THE MATCH TO RELEASE THE
STORED CHEMICAL
ENERGY (phosphorous and
a chlorate mix)
Potential Energy increases, Kinetic Energy decreases
Highest potential Energy, no kinetic Energy
Kinetic Energy increases, no potential energy
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.
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.
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.
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.
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.
Ancient plants and animals transform electromagnet energy from the sun to stored energy. Their remains are coal.
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