Potential

1
Potential Kinetic Energy
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QOD

• What are the 5 types of energy?
• Potential Energy and Kinetic Energy are examples
  of what type of energy?

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Forms of Energy

• Mechanical involves movement or the potential
  for movement (2 forms)
• Potential Energy stored energy (PE)
• -Gravity is the force acting on an object? will
  move if allowed to
• -Impacted by ? Mass, Gravity and Height
• Kinetic Energy - Energy in motion (KE)
• Impacted by - Mass and Velocity

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Equations

• Potential Energy (mass)(gravity)(height)
• PE m x g x h
• Units of measurement
• Mass kg
• Gravity m/s2
• Height meters
• Units for Potential Energy Kgm2/s2 Newton
  meter or a JOULE (J)
• Kinetic Energy (½)(mass)(velocity2)
• KE ½mv2
• Units for Kinetic Energy Newton Meters or
  JOULES (J)

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Examples of PE and KE

• Roller Coasters
• Ski Mountains
• Make mucho on PE KE (you pay for PE-lift
  ticket)
• Rain Forest Zip-Lines
• Water Slides
• Pendulums (physicsplace.com)

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Energy is Conserved
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Conservation of Energy

• PE KE Total Mechanical Energy
• Energy can transfer from PE to KE
• Like a see saw battle (as one gains the other
  loses)
• Ex If total energy 100 at all times
• and there is 25 PE then there would be ___ KE
• You can never gain more energy than you started
  with

8
In Theory 100 PE converts to 100 KE

• So PE KE
• mgh ½ mv2
• You can predict velocity based on height of an
  object
• Velocity square root of (2gh)

9
Think Pair Share
Energy Demo Analysis Activity
10
Physics Place Pendulum Fig.

• www.physicsplace.com
• Choose the top middle book (blue/green, 10th ed.)
• User bergmann12
• Password mustangs1
• Does the total amount of energy in the swinging
  pendulum change?
• How are PE and KE related?
• When the PE is very high, is it possible for the
  KE to be very high as well?
• When the pendulum has a KE of 82 of the total
  energy, what would you assume the PE of the
  pendulum to be?

11
Eulers Disk

• What form of energy is occurring here?
• When the disk starts, does it have more potential
  energy or kinetic energy?
• Does the disk gain energy as it falls? Support
  your answer with your thoughts.

12
Pendulum Calculation

• If h 20 cm and the purple ball has a mass of 10
  kg, then what is the PE of this pendulum?
• What would be the pendulums velocity?

13
Hot Wheels Ramp

• Suppose the car is at rest at the top of the
  ramp. Calculate its PE and KE.
• After the car is rolling down the ramp, calculate
  its PE and KE at the very instant before it is
  stopped at the bottom of the ramp.

14
Nerf Gun

• How could you give the darts in the gun PE (2
  ways)?
• What happens to the PE once you pull the trigger
  of the gun?

15
Bowling Ball Pendulum

• Will this demo hurt?
• Explain your response to 1
• http//video.google.com/videoplay?docid1096316663
  622604841qbowlingballpendulumhlen

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Roller Coaster Physics

• Name two of the forces that affect the motion of
  the car while it moves on the roller coaster.
• Describe how the potential and kinetic energy of
  the car change as the car rolls downhill.
• Can the car reach point X on the track? Why or
  why not?

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Penguin RacePhysics in Action
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Penguin Race Questions

• What type of energy do the penguins acquire as
  they climb?
• What type of energy do the penguins acquire as
  they slide down the track?
• Work transforms energy from one form to the
  other. What is doing the work as the penguins
  slide down the track?
• The D cell battery that powers the toy provides
  what type of energy?
• The penguins can climb due to energy supplied by
  the dry cell battery.
• What does the work in this energy
• transition?

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Penguin Race Questions

• Energy is conserved in a closed system. Does all
  of the dry cell energy go into raising the
  penguins? Why?
• Is the energy the penguins acquire by climbing
  to the top of the ladder equal to the total
  amount of energy at the bottom of the track?
  Why?
• Friction can do work. Lists all places that
  friction exists in this toy.
• Are the penguins at their terminal velocity
  when sliding down the track? How do you know?

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Update Equation Chart

• Potential Energy
• Kinetic Energy