What is energy ENERGY is the ability to cause change There are many different kinds of energy Everything around us has energy YOU have a large amount of energy When change occurs energy is transferred from one object to another ID: 403288
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Slide1
EnergySlide2
What is energy?
ENERGY
is the ability to cause change.
There are many different kinds of energy.
Everything around us has energy – YOU have a large amount of energy.
When change occurs, energy is transferred from one object to another.
Footsteps transfer energy from foot to ground to ears.
Warmth is felt when the sunlight transfers energy to a table or chair.
Where do you see energy?Slide3
Energy of Motion
KINETIC ENERGY
is the energy an object has due to its motion.
KE = ½ x mass x (velocity)
2
The faster something is moving, the more kinetic energy it has.
The heavier a moving object is, the more kinetic energy it has.Slide4
Which one has greater KE?
Two vehicles, a semi and a VW beetle, traveling at 60 mph each
A snowball thrown or a cannonball fired
A bullet fired or a bowling ball rolled down a laneSlide5
Energy of Position
POTENTIAL ENERGY
is the energy an object has based on its position.
PE = mass * gravity * height
Objects very high up have lots of potential energy.Slide6
Which picture has greater PE?
-OR-
YOUSlide7
Total Energy
The
TOTAL ENERGY
is the combination of kinetic and potential energy of a system.
TE = KE + PE
The
LAW OF CONSERVATION OF ENERGY
states that energy can neither be created nor destroyed – it only changes forms.Slide8
Practice!
https://
www.youtube.com/watch?v=izVeVfcfSws
Where is
Higgins’s
potential energy the greatest?
What happens to his kinetic energy as he rolls down the hill?Slide9
Draw a picture of what
Higgins’s
path might have looked like.
What happens
to
Higgins’s
potential energy as he rolls down the hill?
What happens to his total energy?
At the very end, where does all the energy from his motion go?Slide10
Phet
demonstration
We are going to look at an online demonstration, and decide where potential and kinetic energy are the highest.
What is happening as the skateboarder goes up/down the hill?
What is happening to their total energy?
What happens if we change the ramp?Slide11
INTRO
Using the U-shaped track, examine the motion of the skater.
Is energy conserved?
Where is KE, PE the highest?
Click on “Bar graph”
Notice where the skater’s speed is the highest
Click on “Speed”
How does this relate to KE? PE?
Notice where the skater’s height is the highest
Click on “Grid”
How does this relate to KE? PE?Slide12
Friction
Using the U-shaped track, examine the motion of the skater.
Is energy conserved?
If you leave the skater alone, what eventually happens?
Click on “Speed”
Where does this energy go?
Click on “Bar graph”Slide13
Activity! – Human Continuum
During this activity, you will be asked to stand in an area of the room that represents your answer to a question.
You may be asked to defend your answer – be ready to give your reasoning!Slide14
A skater starts at the top of a ramp. Is his energy:
Potential?
Kinetic
?
Thermal?Slide15
A skater is at the bottom of the ramp, quickly
moving up to the other side. His energy is:
Kinetic, potential, or a mix?Slide16
Where is this skater on the ramp, given his energy?
Top (moving up)
Bottom
Middle
Top (moving down)Slide17
Same question – where is this skater?
Top
Middle
BottomSlide18
Top
Middle
B
ottomSlide19
In which position does the skater have the most…?
Kinetic energy
Potential energy
Total energy
A
B
C
D
ESlide20
At
the highest point kinetic energy is
zero
/
maximum
while the potential energy is
zero
/
maximum
.At the lowest point kinetic energy is zero / maximum while potential energy is zero / maximum.Mass affects
/ does not affect the amount of energy.Slide21
As an object falls in gravity, kinetic energy
increases
/
decreases
/
remains the same
.
As an object falls in gravity, potential energy
increases
/
decreases
/ remains the same.As an object falls in gravity, total energy increases / decreases / remains the same.Slide22
An object travelling faster and faster has a kinetic energy that
increases
/
decreases
/
remains the same
.
An object travelling faster and faster has a potential energy that
increases
/
decreases
/ remains the same.As an object speeds up, the total energy increases / decreases / remains the same.As an object slows down, the total energy increases
/ decreases / remains the same.