Transcript NS3310 – Physical Science Studies

NS3310 – Physical Science
Studies
Classical Physics and Plate Tectonics
Rube Goldberg Machine Competition
Physics Questions
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What is mass?
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What is force?
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What is inertia?
How are they related?
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What is momentum?
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What are Newton’s three laws?
How do they account for the motions we observe in nature?
How do friction and gravity work?
Why does the moon orbit the earth, but a bullet shot into the air falls to the ground?
Newton’s 1st Law
 Every Object (mass) retains its state of rest or its
state of uniform straight-line motion (inertia)
unless acted on by an unbalanced force.
Mass Corresponds to Inertia
 Mass is matter occupying Space-time
 Inertia is the tendency of mass
to stay at rest or remain in motion
unless acted on by an outside force
 A force is a push or a pull
Space-Time
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d = vt
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d is distance
(displacement is different from distance)
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v is velocity
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t is time
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Speed is change in distance over time (magnitude)
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Velocity is speed plus direction (vector)
(scale is important)
Newton’s 2nd Law
 The acceleration of an object is directly
proportional to the net force acting on it inversely
to the mass of the object.
Net Forces can be balanced or unbalanced
F = ma
 Force equals mass X acceleration
 Acceleration is change in velocity over time
 There are three ways to accelerate:
– speed up
– slow down
– change direction
A motorist wishes to travel 40 kilometers at an average
speed of 40 km/hr. During the first 20 km, an average
speed of 40 km/hr is maintained. During the next 10 km,
however, the motorist goofs off and averages only 20 km/hr.
To drive the last 10 km and average 40 km/hr, the motorist
must drive:
a) 60 km/hr
c) 90 km/hr
b) 80 km/hr
d) faster than
light
Acceleration Problems
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Roller Coaster Physics
Where is the greatest thrill on a roller
coaster?
Why?
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Which Lane?
Why is a race on a straight track faster than one the same distance on a curved
track? Why is there an advantage to running in the outside lane?
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Run or Walk in the Rain?
Should you run or walk when crossing
a street in the rain without an umbrella?
Momentum
 p = mv
Clowns on Ice
Life Preserver Problem
 Momentum is Conserved
Collisions
– Elastic
– Inelastic
Momentum Problems
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Why are Boxing Gloves Safer than Bare Hands?
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How Can Cats Survive
Long Falls?
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Bed of Nails, Anyone?
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What should you do if you are trapped in
a falling elevator?
Impulse
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Impulse = Ft
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Impulse = Dp (Impulse equals
change in Momentum)
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Why is it easier to accelerate a soccer ball than a bowling ball?
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Can you push your van from the inside?
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Why is it better to push your stalled van than to hit it?
Newton’s 3rd Law
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Whenever two objects
interact, the force exerted
on one object is equal in
strength and opposite in
direction to the force exerted
on the other object.
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Rocket Science
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Support Force is NOT Reaction Force
A Couple of Forces Worth Special
Attention
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Gravity
– Newton’s Gravity (G = m1 X m2 / d2)
 Newton’s
Apple
– Einstein’s Gravity (G = ma of space-time)
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Friction
(Friction is the earth’s reaction force to our pushing against it . Remember,
we are accelerating toward the earth due to the earth’s gravity, we
accelerate toward the earth since the earth’s mass is much greater than
our own)
Inertia is independent of gravity
(Weight is the Force of Gravity on Mass)
 FG = M1 X M2 / d2
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Galileo
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Center of gravity?
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How does Newton’s
gravity differ from Einstein’s gravity?
Projectile Motion
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Projectile Motion is a balance between straight line motion and gravity
– Baseball Physics
– Ballistics
– The Monkey Problem
A zookeeper devises a rubber-band gun to shoot
food to a monkey who is too shy to come down from
the trees. If the monkey does not move, should the
keeper aim above, at, or below the monkey?
If the monkey lets go of the branch at the instant the
keeper shoots the food, should the keeper aim
above, at, or below the monkey to get food to the
monkey in mid-air?
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An Orbit is an example of projectile motion
– What would happen to the moon if the earth disappeared?
Key Concepts
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Newton’s 1st law is known as the law of inertia
Mass is matter (and energy) occupying space-time (E=mc2)
Inertia is the tendency of mass to stay at rest or remain in motion unless
acted on by an outside force
Acceleration a is change in velocity with time
A force is a push or a pull (Newton’s 2nd Law)
F=ma (force = mass X acceleration)
Momentum is mass X velocity
Momentum is conserved
For every action there is an equal and opposite reaction
(Newton’s 3rd Law)
Reaction pairs are specific
Gravity (G) = M1XM2 / d2
Projectile motion is the result of the balance between straight line motion
and gravity
An orbit is an example of projectile motion
Geoblocks
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You will create the model of plate tectonics which will be used on your
practical exam.
Be sure to use the colors indicated for each layer.
Be sure to match the correct top to each block.
Be careful to distinguish sedimentary layers at the very top of some
blocks from the igneous layers (some colors are the same, but the
sedimentary layers are only at the very top of some blocks and on
the tops)
If you have any questions, ask me 
Questions Plate Tectonics Answers
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What is the internal structure of the earth?
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What is the earth’s crust and how did it form?
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What is the difference between ocean crust and
continental crust?
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Why do mountain chains on different continents
have similar rocks and fossils?
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Why do the continents look like a puzzle?
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How can continents move around?
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Okay, so if the plates are moving around, what
happens if they run in to each other?
Plate Tectonics
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The theory of plate tectonics is the
unifying theory of geology.
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The earth is made of many layers: the
solid inner core, liquid outer core, plastic
mantle, and solid crust.
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The earth’s crust is a thin solid layer of
rock floating on the plastic mantle below
it. The crust is broken up into many
plates. Plates can have ocean crust,
continental crust, or
combinations of both.
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Ocean crust is denser than
continental crust, so it floats deeper
in the mantle.
Plate Tectonics
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Where plates move apart as new
crust forms is called a spreading
center or rift zone. This can occur in
the oceans or on land.
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When plates with ocean crust run into
plates with continental crust they are
subducted.
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When two plates with continental
crust collide, mountains form
through orogeny.
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When plates with a combination of
ocean and continental crust collide
they slide against each other along
transform faults.
The Structure of the Earth
 Inner Core
 Outer Core
 Mantle
 Crust
Divergent Plate Boundaries
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Sea-Floor Spreading
 Age of Ocean Floor
 Magnetic Anomalies
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Example of Divergent
Boundary – Mid-Atlantic Ridge
Convergent Plate Boundaries
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Subduction
 Ocean trenches
 Volcanism
 Back-arc basins
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Orogeny
(examples: Himalaya and
Appalachia Mountains
Transform Boundaries
 San Andreas Fault
 Active and Passive Margins
Hot Spots
 Oceanic Hot Spots
Island Chains
 Continental Hot Spots
Key Concepts
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The theory of plate tectonics is the unifying theory of geology.
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The earth is made of many layers: the solid inner core, liquid outer
core, plastic mantle, and solid crust.
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The earth’s crust is a thin solid layer of rock floating on the plastic
mantle below it. The crust is broken up into many plates. Plates can
have ocean crust, continental crust, or combinations of both.
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Ocean crust is denser than continental crust, so it floats deeper in the mantle.
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Where plates move apart as new crust forms is called a spreading center or rift zone. This can occur in the
oceans or on land.
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When plates with ocean crust run into plates with continental crust they are subducted. When two plates with
continental crust collide, mountains form through orogeny. When plates with a combination of ocean and
continental crust collide they slide against each other along transform faults.
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Different types of volcanoes are produced at rift zones and behind subduction zones.
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Hot spots in the mantle form island chains as ocean crust moves above them.
Egg Drop
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1. The device must be of original design.
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2. It can constructed of any the materials placed on the front tables.
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3. Upon the initial release of the device, it must be able to fit within a 10" X 10" X 10" cube. Once the device is released, it may
take any shape or size.
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4. There will be no physical contact with the device and the designer once the device has been released.
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5. The design must allow for easy opening and inspection of the egg.
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6. Repairs requiring additional materials will not be allowed once the competition has begun—accept for "re-closing" after each
inspection.
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7. "Free Fall" indicates the use of gravitational acceleration forces only, therefore no propulsion devices or air drag devices.
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9. Be prepared to clean up your mess, if necessary.
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10. The device will be dropped from the third, second, then first floor of the parking garage. Your package will be inspected to
see that the egg has survived from each height.
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11. Originality will be awarded
Energy
 Energy is the capacity to do work!
 Potential Energy = the potential to do work
 Kinetic Energy = the energy of motion (momentum)
Forms of Energy
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Mechanical (mass)
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Chemical (heat)
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Radiant (light)
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Electrical (electricity and magnetism)
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Nuclear (atomic)
Energy Conversion
 Any form of energy can be converted to any other
form of energy
 Energy is Conserved!
 Entropy (DS = q/T, where T = temperature, so we’ll get back to
this later)
Sources of Energy
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Fossil Fuels
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Biofuels
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Hydrodynamic (water)
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Aerodynamic (wind)
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Geothermal
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Solar
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Hydrogen
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Nuclear
An Interesting Problem
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The electricity consumption in the United States in the year 2001 was about 3600
billion kWh ("kilowatt-hour"), and in the whole world, 13,900 billion kWh (data from
"International Energy Annual"; http://www.eia.doe.gov/emeu/iea/table62.html). A
kWh is a measurement of the amount of energy supplied by 1 kW in one hour. For
example, if a 100-W light bulb is on for 10 hours, the energy used is 1 kWh of energy.
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If we were able to capture all solar radiation arriving on Earth (at the top of the
atmosphere) and convert it to electricity with 100% efficiency, how long would we
need to capture this energy to satisfy the electricity consumption for the whole year
for the United States? The world? (Hint: calculate the cross-sectional area of Earth.)
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Answer:
Cross-sectional area of Earth facing the Sun at any given time = pRe2 = 1.28 X 1014 m2 (
where Re is the Earth’s radius)
The amount of energy received by the Earth in one second is
E =1370 J/s/m2 X 1.28 X 1014 m2 X 1 s = 1.75 X 1017 J
Length of time required to satisfy electricity consumption for one year:
tUSA = 1.30 X 1019J / 1.75 X 1017 J = 74 s (1 min 14 sec)
tWorld = 5.00 X 1019 J / 1.75 X 1017 J = 286 s (4 min 46 sec)
Key Concepts
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Energy is the capacity to do work
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Potential Energy is energy of position relative to gravity
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Kinetic Energy is the energy of motion
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There are many forms of energy, but any one form can be
converted to any other
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Energy is released in collisions
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Energy is always conserved
Earthquake Table
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You must build a structure that will survive an earthquake. You will build your structure
from play dough and paper cards. You must build your structure with the following
specifications:
1. Your building must be of original design.
2. It can constructed only out of the materials provided (you are on a budget).
3. The structure should be at least three stories tall, with a base of at least seven inches by seven inches.
The top floor must measure at least five inches by five inches.
4. The total height must be at least 12 inches.
5. There will be no physical contact with the structure by the designer once the earthquake table has
been started.
Remember - Tectonic Forces
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Tectonic forces include
Plate tectonics
– Compressional forces
– Tensional forces
– Shearing forces
Volcanism
Orogeny (mountain building)
Faulting and Folding
And Intrusions of magma into the crust
Types of Volcanoes
 Quiet
Shield Volcanoes
Hot Spot Volcanoes
Fissure Volcanoes
Pillow Lava
Types of Volcanoes
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Explosive
Magma Chamber
Vent
Crater
Caldera
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Pyroclastic flow
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Cinder Cone
How Dangerous are Volcanoes?
 Volcano Hazards
 Historic Eruptions
Earth Quakes
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Focus
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Epicenter
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Seismic Waves
Primary Waves
Secondary Waves
Moho (Mohorhovicic Discontinuity)
Type of Faults
 Normal Fault
 Reverse Fault
 Strike-Slip Fault
 Horst and Graben
Folding
 Anticlines
 Synclines
Intrusions
 Batholiths
 Laccoliths
 Sills
 Dikes
Key Concepts
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Many forces change the earth’s
surface
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Tectonic forces change the earth from the inside out
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A fault is a break in the earth’s crust
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Tensional, Compressional and Shearing stress on a fault can cause folding of
the crust and earthquakes
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Seismic waves are created by the friction of movement along a fault
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A volcano is a vent of molten rock to the earth’s surface
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Intrusions are formed by magma which does not reach the earth’s surface
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Cartoon Laws of Physics
 Cartoon Laws of Physics
 Falling Hare
 Looney Tunes
Remember
 F=ma
 P=mv
 Impulse=Ft (or DP)
HINT:
Work
Don’t forget the units!
Without units, you don’t have a
complete answer. And, if you
don’t have the right units at the
end, you did something wrong.
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W = Fd
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Force is measured in Newtons (N), or Pounds (lb)
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Distance is measured in meters (m), or feet (ft)
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Work is measured in Joules (J, which = 1 Nm), or FootPounds (ft-lbs)
Power
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Power = W / t
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Work is measured in Joules (J), or Foot-Pounds (ft-lbs)
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Time is measured in hours or seconds (hr, s)
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Power in measured in J/t (Joules per second) or horsepower
(550 ft-lbs/s)
Work Problems
 How do simple machines reduce the amount of
work?
 How do gears work?
 How do engines have horsepower?
Simple Machines
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Simple Machines
Levers
Pulleys
Inclined Planes
– Wedges
– Screws
Fun with Physics
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Roller Coaster Physics
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The Physics of Baseball
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NASCAR Physics
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Physics of Martial Arts
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Movie Physics
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Physics of Superheroes
Key Concepts
Energy is the capacity to do work
 Potential Energy is energy of position relative to gravity
 Kinetic Energy is the energy of motion
 There are many forms of energy, but any one form can be
converted to any other
 Energy is conserved
 Energy is released in collisions
 Energy is always conserved
 Impulse is momentum / time
 Work equals force times distance
 Power equals work divided by time
 Simple machines make work easier by increasing the distance
across which force is applied
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