Transcript Document

PASS Content Standard 3.1
All energy can be considered to be either
kinetic, which is the energy of motion;
potential, which depends on relative
position; or energy contained by a field,
such as electromagnetic waves.
A force that acts
over a certain area.
Pressure =
Force
Area
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Pressure - 2 min
Exert pressure
because of the
motion of their
particles.
Exert pressure
because of the
motion of their
particles.
What is
happening?
Air molecules inside a basketball
press against the material.
The more air in the ball, the less
it will compress and the higher
it will bounce.
Can you dribble
a ball with no air?
Barometers
Measure
Air
Pressure
The pressure
exerted by air
at sea level
is 10.13 N/cm2
Atmospheric pressure
is usually reported by
the “weatherman” in
inches of mercury
“Normal”
atmospheric
pressure is
29.92 in Hg
29.92 inches
of mercury
Is that a lot?
29.92 inches
of mercury
Is that a lot?
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Weather - 27 min
Describe the
characteristics
of a low pressure
air mass
Describe the
characteristics
of a high pressure
air mass
What is a
weather "front"?
How does this picture relate
to atmospheric pressure?
The force of a fluid
that pushes up on
an object in a fluid.
If buoyant force is
equal to the weight of
the object, the object
will be suspended
inside the fluid.
If buoyant force is
greater than the
weight of the object,
the object will
rise in the fluid.
If buoyant force is
less than the weight
of the object,
the object will
sink in the fluid.
Archimedes Principle states that
the buoyant force on a submerged
object is equal to the weight of the
fluid that is displaced by the object.
The pressure in a moving stream
of fluid is less than the pressure
in the surrounding fluid.
The pressure in a moving stream
of fluid is less than the pressure
in the surrounding fluid.
The Bernoulli's Principle
keeps airplanes in the air.
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Flight - 4 min
Forces acting
on an airplane
Thrust
forward force
produced
by the
engine.
Drag
Friction as
the plane
moves
through
the air.
Lift
Produced by
unequal air
pressures
on the wing
surfaces.
Weight
Gravity
pulling
the plane
down.
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The Wright Brothers - 8 min
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Reverse Engineering - 12 min
The bat exerts
about 8000
pounds of force
on the ball.
Contact between
the ball and the
bat lasts only
about 1/1000 sec.
The ball distorts
to about half its
original diameter
when it contacts
the bat.
The decision to
swing has to
be made within
0.04 seconds.
Swing 1/100
second too
soon and the
ball goes foul
down the left
field side.
Swing 1/100
second too
late and the
ball goes foul
down the right
field side.
An aluminum
bat can hit a
baseball 30 feet
farther than a
wooden bat.
In general, a baseball
will curve in the same
direction that the front
of the ball turns.
The faster the spin,
the greater the break.
A corked bat is lighter,
so its swing speed is faster.
But the baseball bounces
off the bat faster than the
cork can store energy that
might be given back to
the ball.
These two factors
combine to make
a corked bat hit the
ball less distance
the a regular bat.
For maximum distance, hit the
ball just under its center of mass.
This always adds
backspin to the ball providing lift.
A batted ball should be able to
travel no farther than 545 Feet.
A 94 mph fastball is thrown
with 1910 rpm backspin.
Hitting the fastball changes the
spin direction - provides 1827
rpm backspin.
442 feet
This reduces the lift
of the batted ball.
442 feet
A 78 mph curveball is thrown
with 1910 rpm topspin.
Hitting the curveball does not
change the spin direction - but
increases backspin to 2643 rpm.
455 feet
This increases the lift
of the batted ball.
455 feet
What is the
mass of a
baseball?
Why does
the ball
slow down
after leaving
the pitcher's
hand?
What is the
maximum
distance a
batted baseball
should be able
to travel?
A baseball travels
400 feet at sea level,
how far would the
same baseball
travel at an altitude
of 5000 feet?
Why do fly
balls travel
farther when
the humidity
is low?
During a
pitch, where
does a
curveball
do most of
its curving?
What
direction
does a
curveball
break?
Does a
corked bat
hit a baseball
farther than
a normal
wooden bat?
Why can a
curveball
be hit
farther than
a fastball?
Fastball: Hold the ball near the ends of your fingers
and throw with a normal overhand delivery.
The ball should roll off your fingers with a backwards
spin (it will tend to rise). Outfielders usually throw the
ball this way because the rising action allows them
to throw it considerably farther.
Curveball: "Choke" the ball (wedge it down between
your thumb and forefinger), and cock your wrist to the left;
the ball snaps down and to the right on release.
The resulting pitch should drop and curve to the left.
Screwball: Throw the ball like a curveball, but reverse
the wrist action and spins. Cock the wrist initially to the
right and "turn the ball over" to the left as you throw it.
The ball should break down and to the right.
Slider: Throw the ball like a football pass, with the wrist
cocked at a 90 degree angle .
The ball should curve slightly down and to the left.
End
Baseball
Physics
A pressure of
2 kg/cm2 in the
first cylinder is
transmitted
through the fluid
to the second
cylinder.
Since cylinder #2
has 5 times the
area of the first
cylinder, the
pressure is
multiplied
5 times.
The greater the
difference in size
between the two
cylinders, the
more the force
is multiplied.
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Energy - 1 min
Energy stored
in an object due
to its position.
Gravitational potential energy,
GPE, is dependent on an
object’s height above the
surface of the earth.
GPE = weight (N) X height (m)
weight = mass (kg) X g (9.8 m/s2)
GPE = mgh
The units are Joules
kilogram meters / s
2
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Potential Energy - 5 min
Chemical Potential Energy energy due to condition
mgh =
1/
2
2
mv
Energy an object
has because of
its motion.
1
KE = 2 MV
2
Potential energy
can be changed
into kinetic energy
and kinetic energy
can be changed into
potential energy.
Potential energy
can be changed
into kinetic energy
and kinetic energy
can be changed into
potential energy.
Potential energy
can be changed
into kinetic energy
and kinetic energy
can be changed into
potential energy.
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Law of Conservation of Energy - 4 min
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Useful Energy Changes - 3 min
There are
5 types
mechanical
heat
chemical
electromagnetic
nuclear
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Forms of Energy - 1 min
There are
5 energy types
Mechanical energy
is associated
with motion.
There are
5 energy types
Heat energy is
the internal
motion of particles.
There are
5 energy types
Chemical energy bonds
atoms and molecules
together.
There are
5 energy types
Electromagnetic energy
is contained in
moving electric
charges.
There are
5 energy types
Nuclear energy
holds the
atomic nucleus
together.
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Atomic Bombs - 4 min
E = energy in Joules
m = mass in kilograms
c = speed of light (300,000 km/s)
Think of matter and energy as two
forms of the same thing that can
be converted from one to another.
Splitting of a
heavy atomic nucleus
Fusing two or more
light-weight atomic nuclei
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Nuclear Reactions - 11 min
Man's first atomic explosion
July 16, 1945, at 5:29:45 a.m.
"Little Boy" was dropped on
Hiroshima, Japan on August 6, 1945.
It weighed about 9,000 pounds
and had an explosive force of
about 20,000 Tons of TNT
Hiroshima after the bomb.
"Fat Man" was dropped on
Nagasaki, Japan on August 9, 1945.
It weighed about 10,000 pounds
and had an explosive force of
about 20,000 Tons of TNT
Nagasaki after the bomb.
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Conservation of energy - 4 min
Electricity is energy associated with charged
particles as they move from place to place
Like charges
repel
Opposite charges
attract
Unequal charges
on an object.
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Lightning - 3 min
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Static Electricity - 6 min
Conduction
Friction
Induction
Conduction
When an object with an excess
of electrons touches a neutral
object, electrons are passed
to the neutral object.
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Conduction - 7 min
Friction
When an object whose electrons
are loosely held rubs against
another object, electrons are
transferred to the second object.
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Friction - 5 min
Induction
A neutral object acquires a charge
from a charged object close by
without contact being made.
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Induction - 12 min
Current flows in
only one direction
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Batteries - 2 min
Current flow changes
direction periodically
All AC electricity
produced in the U.S.
is "60 cycle"
electricity.
•
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Fuel Power Plants - 3 min
There are about 110 nuclear
power plants in the US
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Nuclear Power Plants - 3 min
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Blackout - 3 min
Transformers are used to
change electric voltage.
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Transformers - 1 min
When electricity is supplied to the
primary coil, it magnetizes the core
and produces a voltage in the
secondary coil.
The voltage produced depends
on the ratio of the number
of turns in each coil.
The primary coil below has 10 turns,
while the secondary has 2. The ratio
is 5 to 1 - which means the voltage
produced across the secondary will
be 1/5 the voltage of the primary.
The primary coil below has 3 turns,
while the secondary has 6. The ratio
is 1 to 2 - which means the voltage
produced across the secondary will
be twice the voltage of the primary.
The "pole" transformer
reduces voltage
for the final time.
Amps
Find out WHY
a fuse blows
before replacing
Why do some meters have 5 dials
and other meters have only 4?
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Electric Circuits
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Electric circuits - 4 min
Electric Circuit
Series
Circuit
Parallel
Circuit
Electric Circuit
Series Circuit
Electric Circuit
Series Circuit
Electric Circuit
Parallel Circuit
Electric Circuit
Parallel Circuit
A measure of the energy
available to move electrons
The electric potential
difference between two points
A measure of the amount of
current flowing past a given
point in a given time.
Electric Power
•
C a l c u l a t i n g:
Power =
Voltage X Current
Electric Power
• C a l c u l a t i n g:
Watts =
Volts X Amps
Electric Power
• C a l c u l a t i n g:
Energy =
Power X Time
1.000
0.200
0.100
0.010
0.001
What causes
this force?
A force of attraction
or repulsion due
to an arrangement
of electrons.
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Magnetism - 4 min
The area
around a magnet
where magnetic
forces act.
The forces are concentrated
at the end of a magnet.
Like poles repel.
Unlike poles
attract.
Each of these three magnets
repels the other two.
How could you arrange the
magnets so that each
attracts the other
two instead?
A triangle arrangement
brings the north pole of
each magnet to the
south pole of the others.
Magnetic induction:
the process by which a material
is made into a magnet.
During this process,
atoms in a substance
are aligned.
Temporary magnets:
Materials that are easy to magnetize,
and loose their magnetism quickly.
Permanent magnets:
Materials that are hard
to magnetize, but tend
to stay magnetized.
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Lodestone - 3 min
Magnetosphere:
the region of the earth's magnetic field.
Extends beyond
the atmosphere.
Composed of
charged particles
given off by the sun.
The Earth’s magnetosphere
extends 37,300 miles from
the Earth on the side
facing the sun.
And much
farther on the
side away from
the sun.
A compass is used to detect
the Earth's magnetic field.
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Earth's Magnetic Field - 3 min
Collision of charged particles from
the Sun with charged particles in
the Earth’s upper atmosphere
Collision of charged particles from
the Sun with charged particles in
the Earth’s upper atmosphere
Aurora Borealis
Aurora Australis
Aurora Borealis
Aurora Australis
The ultimate energy source for
the polar auroras is the solar wind.
Polar auroras
go through
cycles with
solar activity.
Date, 2004
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Electricity and Magnetism - 3 min
Produced by a current running
through a coil of wire.
The strength of an
electromagnet is
increased by
wrapping the
coil around an
iron core.
The magnetic field is active
only when the current is flowing.
The more coils of wire,
the stronger magnet.
When a conducting wire
cuts across magnetic
lines of force, a
current is produced.
Convert electric
energy into
mechanical
energy.
magnet
split rings
magnet
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DC motors - 5 min
Convert mechanical energy
into electrical energy.
Archimedes Principle states that
the buoyant force on a submerged
Aobject
cylindrical
masstoand
is equal
the weight of the
bucket
are suspended
fluid that
is displaced by the object.
from a spring scale
above a beaker with
an overflow spout.
Note the scale
reading.
Archimedes Principle states that
the buoyant force on a submerged
Submerge
the mass
object is equal
to the weight of the
by
raising
beaker. by the object.
fluid
thatthe
is displaced
Pour the water from
the catch beaker into
the hanging bucket
to return to the
original scale
reading.