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51 Cards in this Set

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WORK
WORK/DISTANCE
WORK ENERGY BEING USED
WORK DEFINED
lIFTING YOU DVD OFF THE FLOOR AND PUDING IN YOUR TV IS WORK, HOWEVER, THE FORCE IS EQUAL TO THE WEIGHT OF DVD, WHILE THE DISTANCE IS EQAUL TO THE HEIGHT OF YOUR TV
MOORE ABOUT WORK
SOMETIMES YOU MAY BE DOING MORE WORK IN A PHYSICAL SENSE, THEY MOVE IN A HORIZONTAL DIRECTION, SO THE DIVD IS A VERTICAL ORIENTED FORCE.
JOULE
tHE SI UNIT FOR WORK
pOWER
RATE AT WHICH WORK CAN AND HOW QUICKLY BE DONE
CALCULATE POWER=DIVIDE WORK DONE/TIME IT TOOK TO DO THE WORK
wATT
THE SI UNIT FOR POWER
ENERGY
ABILITY TO DO WORK
SI UNIT IS THE NEWTON METER (Nm)
eNERGY IS Squaler quantity
Energy may recoved after use
First of two types of energy-Potential Energy
Energy that is waiting to be converted into power or stored energy
Gasoline in a sitting car is potential energy
a rock in sitting on top of cliff has much potential energy
The higher the rock is lifted the more potential energy it has
Potential energy formula
POTENTIAL ENERGY=FORCE* DISTANCE OR MGH
M=MASS OF AN OBJECT
G=ACCELERATION DUE TO GRAIVITY
H=THE CHANGE OF HEIGHT
KINETIC ENERGY-
this is the energy of motion.
Object moves=potenital energy
heavier objects the faster it moves and the more KIn. eng. it has
exp. Impact of speed when a car hits a wall
KINETIC ENERGY =1/2 MV2
M=MASS
V=VELOCITY
KINETIC ENERGY =1/2 MV2
M=MASS
V=VELOCITY
**ENERGY INCREASES WITH VELOCITY SQUARED, IF YOUR CAR IS GOING TWICE AS FAST, YOU HAVE 4 TIMES THE KINETIC ENERGY
heat energy
Heat is substance
heat energy of sub. is a measure of how active atoms/molecules that make up that substance are
Hot subs. move around more radically
cold subs move around more slowly
When particles are excited they take up lots space
calm down part.=less space
conduction-Heat can travel through a hot object or cooler object
Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences.

The thermal energy, in the form of continuous random motion of the particles of the matter, is transferred by the same forces that act to support the structure of matter, so can be said to move by 'physical' contact between the particles.

It should be noted that heat can also be transferred by Thermal radiation and/or convection, and often more than one of these processes occur in a particular situation.

The law of heat conduction, also known as Fourier's law, states that the time rate of heat transfer through a material is proportional to the negative gradient in the temperature and to the area at right angles, to that gradient, through which the heat is flowing:


where

Q is the amount of heat transferred,
t is the time taken,
k is the material's conductivity. (this generally varies with temperature, but the variation can be small over a significant range of temperatures for some common materials.),
S is the surface through which the heat is flowing,
T is the temperature.

Linear heat flowThe above differential equation, when integrated for a simple linear situation (see diagram), where uniform temperature across equally
convection-Heat can travel through a hot object or cooler object
ex stove
radiation-Heat can travel through a hot object or cooler object
ex car
Tempature is what?
is a measure of the average kinetic energy of molecules: in the US degrees is measured in Farienhiet, while countries using metric use celsius. Scientists may use Kelvin (K) for more technical terms.
ELECTRICIT AND MAGNETISM
ELECTRICITY
Protons and Neutrons
Electric charge is the property of electrons and protons. Electrons are said to be negatively charged while protons are said to be positively charged. Electric charge is a "conserved" property, meaning that it behaves like a substance and can be moved from place to place. IO also means that energy is neither created nor destroyed, it can only be converted from electrical energy (one form) to any other form of energy (like heat, kinetic energy, mechanical energy, etc.) 6,242,000,000,000,000,000 (6.242 x 10^18) electrons or protons make up 1 Coulomb of charge.


[change] Examples
Electric current is the uniform motion of electric charge. When 1 Coulomb of electrically charged particles move past a point in 1 second, the existing current is 1 Ampere.
Electric voltage is the "push" behind the current. It is the amount of work per electric charge that an electric source can do. If a source can do 1 Joule of work on 1 Coulomb of charge, it has a 1 Volt of electric potential.
Electric resistance is the ability of a substance to resist the flowing of the current, i.e. to reduce the amount of current that flows through the substance. If an electric voltage of 1 Volt maintains a current of 1 Ampere through a wire, the resistance of the wire is 1 Ohm. When the flow of current is opposed (resisted) energy is gets used or gets converted to other forms (eg. heat, etc.).
Electric energy is the ability to do work by means of electric devices. Electric energy is a "conserved" property, meaning that it behaves like a substance and can be moved from place to place. Electric energy is measured in Joules or kilowatt-hours (kwh). Electric energy is the amount of energy that an amount of electricity can produce at a time.
Electric power is the rate at which electric energy is being used, stored, or transferred. Flows of electrical energy along power lines are measured in Watts. If the electric energy is being converted to another form of energy, it is measured in Watts. If it is stored (as in electric or magnetic fields), it is measured in Volt-Ampere-Reactive. If some of it is converted and some of it is stored, it is measured in Volt-Amperes.
CONDUCTORS
These are materials in which it is easy to get electrons to move and provide a flow of electric current.
Conductors are mostly metals such as gold, silver, copper, iron and lead.
Carbon is a conductor as well as some gases (as in fluorescent tubes) and water containing some
chemicals.
These are not perfect conductors and offer some resistance to the flow of current.

The resistance of a conductor (such as a metal rod) is determined by three things:

(1) its length. The longer its length the higher its resistance.
(2) its cross-sectional area. The bigger this is the lower is its resistance.
(3) the material of which it is made.

All materials have RESISTIVITY.
The higher the value of resistivity the higher the resistance.
It is measured in OHM METERS.

length x resistivity
Resistance = -------------------------------
cross-sectional area
INSULATORS
Electrical insulation is a material or object that resists the flow of electric current. When a voltage is placed across an insulator, very little current flows. An object intended to support or separate electrical conductors without passing current through itself is called an insulator. An insulator is a material with atoms that have tightly bonded valence electrons and resist the flow of electrical current.

The term electrical insulation has the same meaning as the term dielectric.

Some materials such as silicon dioxide or teflon are very good electrical insulators. A much larger class of materials, for example rubber-like polymers and most plastics are still "good enough" to insulate electrical wiring and cables even though they may have lower bulk resistivity. These materials can serve as practical and safe insulators for low to moderate voltages (hundreds, or even thousands, of volts).

Electrical insulation is the absence of electrical conduction. Electronic band theory (a branch of physics) predicts that a charge will flow whenever there are states available into which the electrons in a material can be excited. This allows them to gain energy and thereby move through the conductor (usually a metal). If no such states are available, the material is an insulator.

Most (though not all, see Mott insulator) insulators are characterized by having a large band gap. This occurs because the "valence" band containing the highest energy electrons is full, and a large energy gap separates this band from the next band above it. There is always some voltage (called the breakdown voltage) that will give the electrons enough energy to be excited into this band. Once this voltage is exceeded, the material ceases being an insulator, and charge will begin to pass through it. However, dielectric breakdown is usually accompanied by physical or chemical changes that permanently degrade the material's insulating properties.

Materials which lack electron conduction must also lack other mobile charges as well. For example, if a liquid or gas contains ions, then the ions can be made to flow as an electric current, and the material is a conductor. Electrolytes and plasmas contain ions and will act as conductors whether or not electron flow is involved.


[edit] Telegraph and power transmission insulators
Electricy is found in nature electrical currents flow through Earth's Atmosphere, the result becomes lighting
while nerve implulses in our body are actuall electrical currents moving between our brain and spinal cord and muscles. Electricity has been harnessed by humans by electric circuits, batteries, etc.
mAGNETISM
magnetism, forceof attraction or repulsion between various substances, especially those made of iron and certain other metals; ultimately it is due to the motion of electric charges.
The way nature creates a force on one another, it magnetism the movement of electrical particles
ELECTROMAGNETISM
Electromagnetism is the physics of the electromagnetic field: a field which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles.

The magnetic field is produced by the motion of electric charges, i.e. electric current. The magnetic field causes the magnetic force associated with magnets.
What is a wave?
Wave is a distrubance that moves through a medium, carrying energy but not matter. Waves in ocean are caused by energy moving through the water. LIke when you skip a stone, the energy has been transferred to teh ripples in teh water
waves can be what
Longitudinal, transverse, surface, electromanetic or mechanical
Waves have certain parts and characteristics-AMPLITUDE
Height of the wave
Waves have certain parts and characteristics-wavelength
the distance from one wavetop or crest to the next
Waves have certain parts and characteristics-pahase shift
describes how far to teh left or right the wave slides
Waves have certain parts and characteristics-frequency
refers to how many waves are made per time interval ( how many waves per sec., or cycles of sound)
Waves have certain parts and characteristics-Interference
When one wave passes thorugh another
Waves have certain parts and characteristics-Reflection
This is a property in whih the direction of waves changes when waves bound off a barrier
Waves have certain parts and characteristics-Frefraction
a change in the direction of waves when they pass from one medium to another, teh speed and wavelength of the waves also change
Diffraction
A change in the direction of waves as they pass thourhg an opening or around a barrier in ther path
Gigt is what
electormmagtnetics radiation ( a wave of energy ad magnetic compontnets: some of these waves become visable light, whoile others are nonvisable, but found in the sprectrim of light
What did Al Einstien contribute to:
the photone light behaves as it was made of both waves and particles
refraction
property is what forces scientis to use different media at times to look at specimens through a miroscope.
reflection
Light waves off a mirrored image.
diffraction
property of not a very substantiona for light indeed, when there is an obstacle in the bath of light a shadeow forms behind the obstacle where there is no light
each individual wavelength with the spectrum of visible light wavelenghts is representive of a particula color
that is, when light of a particular wavelength using a prism, illustrating the phenomeeon of dispersion
Diffraction
A change in the direction of waves as they pass thourhg an opening or around a barrier in ther path
Gigt is what
electormmagtnetics radiation ( a wave of energy ad magnetic compontnets: some of these waves become visable light, whoile others are nonvisable, but found in the sprectrim of light
What did Al Einstien contribute to:
the photone light behaves as it was made of both waves and particles
refraction
property is what forces scientis to use different media at times to look at specimens through a miroscope.
reflection
Light waves off a mirrored image.
diffraction
property of not a very substantiona for light indeed, when there is an obstacle in the bath of light a shadeow forms behind the obstacle where there is no light
each individual wavelength with the spectrum of visible light wavelenghts is representive of a particula color
that is, when light of a particular wavelength using a prism, illustrating the phenomeeon of dispersion
Light Prism
Each indiviual wavelength with the spectrum of visible light wavelengths is representive of a articular color
Isaac Newton was able to do what to seperate light into is diffreint-Dispersion
wavelength using a prism, illustiraing the phenomenon of dispersion
Different wavelengths of light
(that each correspond to a different color) will bend to verying degrees when passed through a prism and therefore can be separated
Frequency of a sound wave
describes how often the particles of the medium vibrate when a wave passes through, measured as the number of complete vibrations per unit of time, a commonly used u nit for frequency is the Hertz (Hz) 1 hertz= 1 vibration per second
Pitch sound the corrosponds
to a high frequency and a low pitch sound corrosponds to low frequency
The teacher must understand the concepts of work, power, and energy and how they are related
with an understanding also the diffreint types of energy.
2) The teacher must have knowledge of how electric and magnetism are generated and the relationship between teh two
3) Finally, the teacher must understand teh basic characteristics and principles of waves
and apply them to important examples such as light waves and sound waves