Essential Information & explanations, latest texts & monographs on
Energy.
Eating for Life: Your Guide to Great Health, Fat Loss and Increased Energy! by Bill Phillips
The Power of Full Engagement: Managing Energy, Not Time, is the Key to High Performance and Personal Renewal by Jim Loehr
Positive Energy : 10 Extraordinary Prescriptions for Transforming Fatigue, Stress, and Fear intoVibrance, Strength & Love by Judith Orloff
The End of Oil : On the Edge of a Perilous New World by Paul Roberts
The Oil Factor: How Oil Controls the Economy and Your Financial Future by Donna Leeb
Smartest Guys in the Room: The Amazing Rise and Scandalous Fall of Enron by Bethany McLean
The Party's Over: Oil, War and the Fate of Industrial Societies by Richard Heinberg
Out of Gas: The End of the Age of Oil by David Goodstein
The Halliburton Agenda : The Politics of Oil and Money by Dan Briody
Hands of Light : A Guide to Healing Through the Human Energy Field by Barbara Brennan
Brand Portfolio Strategy : Creating Relevance, Differentiation, Energy, Leverage, and Clarity by David A. Aaker
Energy Medicine by Donna Eden
Building With Structural Insulated Panels (Sips): Strength and Energy Efficiency Through Structural Panel Construction by Michael Morley
The Radioactive Boy Scout : The True Story of a Boy and His Backyard Nuclear Reactor by KEN SILVERSTEIN
The Only Astrology Book You'll Ever Need by Joanna Martine Woolfolk
Energy
Commonly, energy is energy development, the field concerned with providing abundant and accessible energy to all humans.
Energy is a quantifiable state function of every physical system. Energy allows one to predict how much work a physical system could be made to do, or how much heat it can exchange. In general, the presence of energy is detected by an observer or system any time there is a change in the properties of another object or system. This is where the early exploration of the nature of energy began. As our understanding of the nature of energy progressed, scientists found it to exist in many forms not readily observable by the average unaided observer. Empirical observations have shown that the total quantity of energy is conserved. This makes the concept of energy very important in physics.
Table of contents showTocToggle("show","hide")
1 Units
2 Transfer of energy
2.1 Work
2.2 Heat
3 Conservation of energy
4 Kinetic energy
5 Potential energy
6 Internal energy
7 Total energy (as a series)
8 Examples
9 See also
10 External Links
11 Further reading
12 References
Units
The SI unit for both energy and work is the joule (J), named in honor of James Prescott Joule and his experiments on the mechanical equivalent of heat. In slightly more fundamental terms, 1 joule is equal to 1 newton metre, and in terms of SI base units, 1 J equals 1 kg m²/s². (Conversions. In cgs units, one erg is 1 g cm²/s². The imperial/US unit for both energy and work is the foot pound.)
The unit used for energy in the form of electricity and billing of companies and households is kilowatt-hour that equals 3,6·106 J = 3600 kJ. A unit that is used in the particle physics is electronvolt 1 eV = 1,602 176 462·10-19 J
Transfer of energy
Work
Main article: Work (physics).
Work is a measure of energy expended in applying force over a distance. Performing work requires energy, and thus the amount of energy in a system limits the maximum amount of work that a system could conceivably perform.
For example, in the one-dimensional case of applying a force through a distance, the energy required is ∫ f(x) dx, where f(x) gives the amount of force being applied as a function of the distance moved.
Note, however, that not all energy in a system is stored in a recoverable form; thus, in practice, the amount of energy in a system available for performing work may be much less than the total amount of energy in the system.
Heat
Main article: Heat.
Heat is an amount of energy which is usually linked with a change in temperature or in a change in phase of matter. In chemistry, heat is the amount of energy which is absorbed or released by a given chemical reaction.
The relationship between heat and energy is similar to that between work and energy. Heat flow from areas of high temperature to areas of low temperature. All objects (matter) have a certain amount of internal energy that is related to the random motion of their atoms or molecules. This internal energy is directly proportional to the temperature of the object. When two bodies of different temperature come in to thermal contact, they will exchange internal energy until the temperature is equalized. The amount of energy transferred is the amount of heat exchanged. It is a common misconception to confuse heat with internal energy, but there is a difference: the change of the internal energy is the heat that flows from the surroundings into the system plus the work performed by the surroundings on the system.
Conservation of energy
The first law of thermodynamics says that the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system. This law is used in all branches of physics. Noether's theorem relates the conservation of energy to the time invariance of physical laws.
Kinetic energy
Kinetic energy is that portion of energy associated with the motion of a body.
The equation hereabove says that the kinetic energy (Ek) is equal to the integral of the dot product of the velocity (v) of a body and the infinitesimal of the body's momentum (p).
For non-relativistic velocities, we can use the Newtonian approximation
where Ek is kinetic energy, m is mass of the body, v is velocity of the body
At near-light velocities, we use the relativistic formula:
where v is the velocity of the body, m is its rest mass, and c is the speed of light in a vacuum.
The first term, γmc2, is the total energy of the body, and the second term, mc2, is again the rest mass energy.
Potential energy
Main article: Potential energy.
Potential energy is energy associated with being able to move to a lower-energy state, releasing energy in some form. The potential energy can be stored as gravitational energy, elastic energy, chemical energy, rest mass energy or electrical energy.
For example a mass released above the Earth has energy resulting from the gravitational attraction of the Earth which is transferred in to kinetic energy.
Equation:
where m is the mass, h is the height and g is the value of acceleration due to gravity at the Earth's surface.
Internal energy
Main article: Internal energy.
Internal energy is the kinetic energy associated with the motion of molecules, and the potential energy associated with the rotational, vibrational, and electric energy of atoms within molecules. Internal energy, like energy, is a quantifiable state function of a system.
Total energy (as a series)
In the form of a Taylor series, the relativistic formula for total energy can be written:
Hence, the third and higher terms in the series correspond with the "inaccuracy" of the Newtonian approximation for kinetic energy in relation to the relativistic formula.
Examples
An example of the conversion and conservation of energy is a pendulum. At its highest points the kinetic energy is zero and the potential gravitational energy is at its maximum. At its lowest point the kinetic energy is at its maximum and is equal to the decrease of potential energy. If one unrealistically assumes that there is no friction, the energy will be conserved and the pendulum will continue swinging forever.
Another example is a chemical explosion in which potential chemical energy is converted to kinetic energy and heat in a very short time.
See also
External Links
Further reading
- Feynman, Richard. Six Easy Pieces: Essentials of Physics Explained by Its Most Brilliant Teacher. Helix Book. See the chapter "conservation of energy" for Feynman's explanation of what energy is, and how to think about it.
References
The above article is adapted from from Wikipedia All Wikipedia article text is available under the terms of the GNU Free Documentation License
Recent related patents from USPTO:
6738958: Modifying a hierarchical representation of a circuit to process composite gates
6738921: Clock controller for AC self-test timing analysis of logic system
6738920: Method for deriving addresses for a plurality of system components in response to measurement of times of receipt of two signals by each component
6738919: Signal trace phase delay
6738888: TLB with resource ID field
6738859: Method and apparatus for fast aerial image simulation
6738856: External display peripheral for coupling to a universal serial bus port or hub on a computer
6738744: Watermark detection via cardinality-scaled correlation
6738743: Unified client-server distributed architectures for spoken dialogue systems
6738741: Segmentation technique increasing the active vocabulary of speech recognizers
6738739: Voiced speech preprocessing employing waveform interpolation or a harmonic model
6738734: Empirical mode decomposition apparatus, method and article of manufacture for analyzing biological signals and performing curve fitting
6738733: G.723.1 audio encoder
6738726: Apparatus and method for measuring the maximum speed of a runner over a prescribed distance
6738724: Two-stage multiwavelength thermal radiation analyzer
6738720: Apparatus and methods for measurement of density of materials using a neutron source and two spectrometers
6738715: Method for attenuating noise in seismic data
6738714: Vehicle self-carried positioning method and system thereof
6738707: Cylinder air charge estimation system and method for internal combustion engine including exhaust gas recirculation
6738706: Method for estimating engine parameters
6738702: Method for particulate filter regeneration in vehicles having an automatically controlled transmission
6738697: Telematics system for vehicle diagnostics
6738696: Controller for vehicle with information providing function and recording medium
6738693: Multiple virtual meters in one physical meter
6738692: Modular, integrated power conversion and energy management system
6738683: Apparatus and method for cleaning a bell jar in a barrel epitaxial reactor
6738673: Method for catheter mapping and ablation
6738672: Miniature implantable connectors
6738671: Externally worn transceiver for use with an implantable medical device
6738670: Implantable medical device telemetry processor
6738669: System and method for multichamber cardiac stimulation with ventricular capture verification using far-field evoked response
6738668: Implantable cardiac stimulation device having a capture assurance system which minimizes battery current drain and method for operating the same
6738667: Implantable medical device for treating cardiac mechanical dysfunction by electrical stimulation
6738666: Detection of orthostatic hypotension using positional data and cross-check data
6738665: Detection of late atrial extrasystoles in an active implantable medical device such as pacemaker defibrillator, cardiovertor and/or multisite device
6738664: Method of and apparatus for atrial and ventricular defibrillation or cardioversion with an electrical waveform optimized in the frequency domain
6738663: Implantable device and method for the electrical treatment of cancer
6738661: Apparatus and methods for the controllable modification of compound concentration in a tube
6738659: Optical imaging using the temporal direct reflective signal from a minimized pulse width laser
6738657: Customized surgical fixture
6738653: Metabolism monitoring of body organs
6738652: Classification and screening of test subjects according to optical thickness of skin
6738650: Radiation shielding tri-band antenna adapted to provide dual band polarizations
6738647: Method and system for expanding the data payload of data messages transported via a cellular network control channel
6738642: Communication device and method of operating communication device
6738640: Radio communication system
6738617: Controller for reducing latency in a group dormancy-wakeup process in a group communication network
6738608: Frequency-timing control loop for wireless communication systems
6738599: Assembly, and associated method, for facilitating channel frequency selection in a communication system utilizing a dynamic frequency selection scheme
Updates and comments at Essential Facts blog
World Class Photographers
Some philosophical movements
|
|
Interesting Links
Latest Dowloadable
Energy PDF s & Ebooks
Top PDF and eBook Downloads
Bibliographic Resources
Dates
20-th Century
20-th Century Details
Chromosomes and Genomics
Sports
Kitchen Knowledge
Hollywood Icons
Classical Music
Music Directory.
Music: Jazz
Music: Rock
Music: Country
Music: Popular A-E
Music: Popular F-L
Music: Popular M-S
Music: Popular T-Z
Mythology
Philosophy
Politics
Retirement
Agriculture
Agriculture: Flowers
Agriculture: Gardening
Biology
Biology & Biologists
Cell Science
Cell Science: Cells
Cell Science: Stem Cells
California
Cats & Dogs
Ethics
Logic
The Greats
Architectural Dates & Places
Styles ABC
Styles DTOI
Styles JTON
Styles OTOZ
Buddhism
Marketing
Psychology
Enginering Systems 1
Mathematics
Classic Authors
Fear No Exams
Characters & countries
Law & Legal Topics
Linguistics
Movies
Most successful Movies
Science Plus
Science & Computers
Quantum Theory
|