Energy: IPC and Beyond

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Day 1 Types of Energy Storage
Energy
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What is Energy?

• Def Ability to cause change in a system
• Unit? joules
• Symbol? E

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Energy can be transformed from one form to
another.
Mechanical Energy
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Energy Storage

• Energy is energy
• There are no different kinds
• There are simply different ways of storing energy
  within a system
• For Example
• You can store information in a book, on a
  computer hard drive or CD
• No matter how it is stored it is the same
  information

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The Total Energy (ET) of a closed system is
equal to the sum of its mechanical and internal
energies
Energy Storage

• The 2 Major Types are Mechanical Internal
• ET Emec Eint

Can change motion
Energy of the particles
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Mechanical Energy
Em

Def Can cause a change in motion
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Kinetic Energy (KE)
Ek

• Def The energy stored with the actual motion of
  the object
• depends on mass and velocity

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Potential Energy (PE)

• Def energy due to the position of the system
  relative to another object
• usually involves a field (i.e. - gravity,
  magnets, etc.)

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Gravitation Potential Energy (GPE)

• Def energy due to an objects position (height)
  above the ground
• Depends on mass and distance (height)

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Elastic Potential Energy (ELPE)

• Def energy due to a system being stretched or
  compressed

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Electromagnetic Potential Energy

• Def energy due to position in an electric or
  magnetic field

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Chemical Energy

• Energy is not stored in the bond
• Atoms store the energy due to their position
  relative to each other

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Have you "lost" energy?

• Internal energy that the system does not use
  again is called Dissipated Energy
• Symbol DE or ED
• Usually from friction or when the object is
  deformed

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Where did all the Energy go?
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The big picture so far
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Word Bank KE GPE ELPE E M DE
What Kind of Energy???
GPE EM
A curling iron heating on the edge of the counter.
A magnet holding family pictures of the
refrigerator.
GPE EM
A sling shot just in launch position.
ELPE
Hockey puck slowing down on an ice rink.
KE DE
KE GPE
A rock falling off a steep cliff.
KE GPE DE
A child sliding down a playground slide.
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Bar Graphs Energy Transformations
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System vs. Surroundings

• System (it) only the factors we are paying
  attention to
• Surroundings everything else
• You MUST define your system

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Energy Bar Graphs

• Bar Graphs are used to represent how energy is
  stored in a system
• Your set up will look like this
• Initial Bar Graph
  Final Bar Graph
• GPE KE ELPE DE System Definition
  GPE KE ELPE DE

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Bar Graph Practice

• A ball is held at rest 1m above the ground and it
  is then released and has fallen halfway to the
  ground
• Initial Bar Graph Final
  Bar Graph
• GPE KE ELPE DE System Definition
  GPE KE ELPE DE

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Law of Conservation of Energy
Newtons Cradle

• The total energy of a closed system remains
  constant.
• Closed system means no energy enters or leaves
  the system

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Open system, the real world, KE causes friction,
skater eventually comes to a stop
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• The total energy did not change.
• Some of the energy got shifted from mechanical
  energy to internal energy.
• KE ?Thermal Energy

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What Kind of Energy???
GPE EM
A curling iron heating on the edge of the counter.
A magnet holding family pictures of the
refrigerator.
GPE EM
A sling shot just in launch position.
ELPE
Hockey puck slowing down on an ice rink.
KE DE
KE GPE
A rock falling off a steep cliff.
KE GPE DE
A child sliding down a playground slide.
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Bar Graph Practice
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What types of energy are shown below?

• Mechanical and Dissipated Energy
• (friction)

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What type of energy is shown below?

• Chemical Energy

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What types of energy are shown below?

• Electrical, Mechanical and
• Electromagnetic Energy

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What type of energy is shown below?

• Chemical Energy (yummy)

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What type of energy storage is shown below?

• Thermal Energy

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• Draw a flow map showing the flow of energy
  transformations in a car from starting vehicle to
  driving. You should have 5 different types of
  energy.

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Energy Transfer
Sound (mechanical)
Electrical
Thermal
Mechanical
Electrical
Chemical
Electrical
Light (Electromagnetic)
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Calculations
Energy
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Kinetic Energy

• KE ½ mv2
• Changing velocity affects KE more than changing
  mass

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Kinetic Energy Practice Problem
How much kinetic energy does a 75kg car as it
travels at 25m/s?
Variables Formula PC Answer w/units

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Gravitational Potential Energy

• GPE mgh
• Mass x gravity x height above the earth

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Potential Energy Practice Problem
A 25Kg statue is dangling from a crane 20m above
the ground. How much potential energy does the
statue have? How much kinetic energy would it
have if it fell?
Variables Formula PC Answer w/units

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What is the potential energy of the rock? A
59,900 J B 64,600 J C 93,100 J D 121,600 J