Download Kinetic and Potential Energy Notes

Potential and Kinetic Energy
Energy
• The ability to do work
• The Two types of
mechanical energy
•Potential - stored
•Kinetic - moving
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What is Work?
Work - occurs when a force causes an
object to move in the direction of
that force
• When one object does work on another,
energy is transferred.
• Work is a transfer of energy
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1. Tennis player can do work on her racket
because she has energy.
2. Energy transfers from person to racket. The
racket gains the ability to do work on the ball.
3. Racket hits ball, energy is transferred from
racket to ball.
Potential and Kinetic Energy
Potential Energy
• Stored energy in an
object
• Due to position or
shape
• “Energy of position”
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1) The energy it takes to pull back the
bow is stored until the bow is released!
2) The energy is then transferred to the
arrow.
Potential and Kinetic Energy
Gravitational Potential
Energy
When you life an object,
you do work on it by
using a force that
opposes gravity
•Depends on the weight of
the object and its height
above the earth’s surface.
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A
Which ball has the
greatest potential
Energy?
B
PEg = (mass)(height)(Force of gravity)
Quick Action
• Get with a partner and discuss the
last theme park ride you were on.
• Make a list of the points on each ride
where you had the greatest potential
energy.
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Potential and Kinetic Energy
Kinetic Energy
• Energy of motion
• Dependent on the mass
and velocity (speed) of
an object
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• The amount of kinetic energy is
determined by its
speed/velocity and its mass.
• The faster an object in moving
the greater its kinetic energy.
Which object has the greatest speed?
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H = 20m
Kinetic Energy
A
H = 10m
Potential and Kinetic Energy
B
Potential and Kinetic Energy
Kinetic Energy
The greater the mass the greater
the kinetic energy.
A
Which ball has the greatest kinetic
energy?
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B
Kinetic =
Energy
½ *m*v2
25 m/s
20 m/s
1 Which vehicle has the most kinetic energy? The big truck
2 Why? Greatest mass and high velocity
3 Which vehicle has the least kinetic energy? Smaller car on
4 Why? Lower mass and least velocity
left
25 m/s
Quick Action
• Get back with your partner to discuss
the last theme park ride you were on.
• This time make a list of the points on
each ride where you had the
greatest kinetic energy.
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Mechanical Energy - the total energy of motion and position
of an object (sum of the KE and PE)
MECHANICAL ENERGY = Potential energy + Kinetic energy
ME = PE + KE
Can be all potential
Can be all kinetic
Can be both!
• As potential energy increases (or decreases),
kinetic energy decreases (or increases)
• As potential or kinetic energy changes,
mechanical energy stays the same
Quick Action – INB Template
• Cut out the Venn
Diagram and title.
• Glue the title at the top
of page in INB.
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Venn Diagram
Potential Energy
Kinetic Energy
• Energy of position
• Energy of motion
• Not moving
• Increases as motion
increases
• Increases based on
position or height
• Example:
• Example:
Both
• Types of Energy
• Transforms into other types of
energy
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Potential and Kinetic Energy
Transformation of Energy
Bouncing Ball
Several energy transformations happen when a ball is dropped on
surface and bounces up again.
PE - maximum
KE - none
PE - decreasing
KE - increasing
PE – none
KE - maximum
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PE – maximum
KE - none
Potential and Kinetic Energy
Transformation of energy
Pendulum
Several energy transformations
take place as the pendulum
bob swings.
A – PE maximum - KE minimum
B – KE maximum - PE minimum
C – PE maximum - KE minimum
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A
C
B
Quick Action – INB Template
•
•
•
•
Cut out the next three templates.
Glue bottom template into your INB.
Glue middle along the skinny tab one on top of the other.
The roller coaster will be glued on top and upside down so that it flips up and can
be seen while working on sheet two.
Bottom
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Middle
Top
Potential and Kinetic Energy
Transformation of energy
Roller coaster
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Tuesday December 20, 2016
Talk about it Tuesday!
What do you want to be when
you grow up?
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Potential and Kinetic Energy
Transformation of Energy
Roller coaster
PE = 100%
KE = 100%
PE = 75% KE = 25%
KE = 75% PE = 25%
PE KE
PE KE
PE KE
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PE KE
Quick Action
1. Stand up and find a partner to work with.
2. Brainstorm a way to demonstrate potential and
kinetic energy to the class.
3. Be able to point out the point in your
demonstration when potential/kinetic energy is
greatest and least.
4. Sketch your scenario on the bottom page of
your ISN packet
5. Share this information with the class as your
teacher calls on you.
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Guided Reading and Section Review
•Switch papers with someone
at your table
•Grade their work
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Potential and Kinetic Energy
Decide if each
situation is an example
of kinetic or potential
energy.
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Situation
Standing on the end of
a diving board.
Potential
Kinetic
X
Falling from the top of
a ladder.
X
A rubber band pulled
back as far as it can go.
X
Water in a lake behind
a dam.
X
Baseball just before it is
released by the pitcher
X