Transcript Energy: IPC and Beyond

Def: Ability to
cause change
in a system
• Unit joules
• Symbol E
Energy can be transformed from one
form to another.
UV
• 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
Can
change
motion
•The 2 Major Types are
Mechanical & Internal
•ET = Emec + Eint
The Total Energy (ET) of a
“closed” system is equal to
the sum of its mechanical
and internal energies
Energy
of the
particles
Em
Def: Can cause a
change in motion
Ek
Def: The energy
stored with the
actual motion of
the object
•depends on
mass and
velocity
Def: energy due to
the position of the
system relative to
another object
• usually involves a
‘field’ (i.e. - gravity,
magnets, etc.)
E&M
ELPE
GPE
• Def: energy due to an
Potential
Energy
object’s position (height)
above the ground
• Depends on mass and
distance (height)
E&M
ELPE
Potential
Energy
GPE
• Def: energy due
to a system being
stretched or
compressed
E&M
ELPE
GPE
Potential
Energy • Def: energy due to
position in an electric
or magnetic field
Internal
Energy
Potential
Energy
Interactional
Energy
Chemical
Energy
Energy is not
stored in the
bond
• Atoms store
the energy
due to their
position
relative to
each other
• 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
The big
picture
so far…
Potential
Energy
Interactional
Potential
EnergyEnergy
Chemical
Energy
Word Bank
KE GPE
ELPE E & M
DE
A curling iron heating on the edge of the counter. GPE
E&M
A magnet holding family pictures of the refrigerator. GPE
E&M
A sling shot just in launch position. ELPE
Hockey puck slowing down on an ice rink. KE
DE
KE
A rock falling off a steep cliff. GPE
KE
A child sliding down a playground slide. GPE
DE
• System (it): only
the factors we are
paying attention to
• Surroundings:
everything else
You MUST define
your system
• Bar Graphs are used to represent how
energy is stored in a system
• Your set up will look like this:
Initial Bar Graph
GPE
KE
ELPE DE
Final Bar Graph
System Definition
GPE
KE
ELPE DE
• 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
GPE
KE
ELPE DE
Final Bar Graph
System Definition
GPE
KE
ELPE DE
The total energy
of a “closed
system” remains
constant.
•“Closed system”
means no energy
enters or leaves
the system
Newton’s Cradle
Open system, the real world, KE causes
friction, skater eventually comes to a stop
•The total energy
did not change.
•Some of the
energy got shifted
from mechanical
energy to internal
energy.
•KE Thermal Energy
A curling iron heating on the edge of the counter. GPE
E&M
A magnet holding family pictures of the refrigerator. GPE
E&M
A sling shot just in launch position. ELPE
Hockey puck slowing down on an ice rink. KE
DE
KE
A rock falling off a steep cliff. GPE
KE
A child sliding down a playground slide. GPE
DE
What types of energy are shown
below?
Mechanical and Dissipated Energy
(friction)
What type of energy is shown
below?
Chemical Energy
What types of energy are shown
below?
Electrical, Mechanical and
Electromagnetic Energy
What type of energy is shown
below?
Chemical Energy (yummy)
What type of energy storage is
shown below?
Thermal Energy
• 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.
Energy Transfer
Sound
(mechanical)
Thermal
Electrical
Mechanical
Chemical
Light
(Electromagnetic)
Kinetic Energy
•KE = ½
2
mv
•Changing velocity
affects KE more than
changing mass
How much kinetic energy does a 75kg car as it
travels at 25m/s?
Variables
Formula
P&C
Answer
w/units
Gravitational Potential
Energy
•GPE = mgh
•Mass x gravity x height
above the earth
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
P&C
Answer
w/units
What is the
potential energy
of the rock?
A 59,900 J
B 64,600 J
C 93,100 J
D 121,600 J