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Fulcrum (mechanics)
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load, and effort, the lever is divided into three types. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage, which is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device, trading off force against movement. Etymology The word "lever" entered English around 1300 from . This sprang from the stem of the verb ''lever'', meaning "to raise". The verb, in turn, goes back to , itself from the adjective ''levis'', meaning "light" (as in "not heavy"). The word's primary origin is the Proto-Indo-European stem , meaning "light", "easy", or "nimble", amo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Machine
A simple machine is a machine, mechanical device that changes the Direction (geometry) , direction or Magnitude_(mathematics) , magnitude of a force. In general, they can be defined as the simplest Mechanism (engineering) , mechanisms that use mechanical advantage (also called leverage) to multiply force. Usually the term refers to the six classical simple machines that were defined by Renaissance scientists: * Lever * Wheel and axle * Pulley * Inclined plane * Wedge (mechanical device), Wedge * Screw (simple machine), Screw A simple machine uses a single applied force to do Mechanical work, work against a single load force. Ignoring friction losses, the work done on the load is equal to the work done by the applied force. The machine can increase the amount of the output force, at the cost of a proportional decrease in the distance moved by the load. The ratio of the output to the applied force is called the ''mechanical advantage''. Simple machines can be regarded as the eleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loom
A loom is a device used to weaving, weave cloth and tapestry. The basic purpose of any loom is to hold the Warp (weaving), warp threads under tension (mechanics), tension to facilitate the interweaving of the weft threads. The precise shape of the loom and its mechanics may vary, but the basic function is the same. Etymology and usage The word "loom" derives from the Old English ''geloma'', formed from ''ge-'' (perfective prefix) and ''loma'', a root of unknown origin; the whole word ''geloma'' meant a utensil, tool, or machine of any kind. In 1404 "lome" was used to mean a machine to enable weaving thread into cloth. By 1838 "loom" had gained the additional meaning of a machine for interlacing thread. Components and actions Basic structure File:Simple_treadle_floorloom,_line_drawing.png, upright=1.5, left, A simple treadle floor loom. Mouse over components for pop-up links. The warp runs horizontally. On the left the warp beam, held from turning by with a weighted trough t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levers Of The Human Body
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load, and effort, the lever is divided into three types. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage, which is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device, trading off force against movement. Etymology The word "lever" entered English around 1300 from . This sprang from the stem of the verb ''lever'', meaning "to raise". The verb, in turn, goes back to , itself from the adjective ''levis'', meaning "light" (as in "not heavy"). The word's primary origin is the Proto-Indo-European stem , meaning "light", "easy", or "nimble", amo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lever (PSF)
A lever is a simple machine consisting of a beam (structure), beam or rigid rod pivoted at a fixed hinge, or '':wikt:fulcrum, fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load, and effort, the lever is divided into Lever#Types of levers, three types. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage, which is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device, trading off force against movement. Etymology The word "lever" entered English language, English around 1300 from . This sprang from the stem of the verb ''lever'', meaning "to raise". The verb, in turn, goes back to , itself from the adjective ''levis'', meaning "light" (as in "not heavy"). The word's primary origin is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . Just as a linear force is a push or a pull applied to a body, a torque can be thought of as a twist applied to an object with respect to a chosen point; for example, driving a screw uses torque to force it into an object, which is applied by the screwdriver rotating around its axis to the drives on the head. Historical terminology The term ''torque'' (from Latin , 'to twist') is said to have been suggested by James Thomson and appeared in print in April, 1884. Usage is attested the same year by Silvanus P. Thompson in the first edition of ''Dynamo-Electric Machinery''. Thompson describes his usage of the term as follows: Today, torque is referred to using d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment (physics)
A moment is a mathematical expression involving the product of a distance and a physical quantity such as a force or electric charge. Moments are usually defined with respect to a fixed reference point and refer to physical quantities located some distance from the reference point. For example, the moment of force, often called torque, is the product of a force on an object and the distance from the reference point to the object. In principle, any physical quantity can be multiplied by a distance to produce a moment. Commonly used quantities include forces, masses, and electric charge distributions; a list of examples is provided later. Elaboration In its most basic form, a moment is the product of the distance to a point, raised to a power, and a physical quantity (such as force or electrical charge) at that point: : \mu_n = r^n\,Q, where Q is the physical quantity such as a force applied at a point, or a point charge, or a point mass, etc. If the quantity is not concen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lever Principle 3D
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load, and effort, the lever is divided into three types. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage, which is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device, trading off force against movement. Etymology The word "lever" entered English around 1300 from . This sprang from the stem of the verb ''lever'', meaning "to raise". The verb, in turn, goes back to , itself from the adjective ''levis'', meaning "light" (as in "not heavy"). The word's primary origin is the Proto-Indo-European stem , meaning "light", "easy", or "nimble", am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia Journalism Review
The ''Columbia Journalism Review'' (''CJR'') is a biannual magazine for professional journalists that has been published by the Columbia University Graduate School of Journalism since 1961. Its original purpose was "to assess the performance of journalism in all its forms, to call attention to its shortcomings and strengths, and to help define—or redefine—standards of honest, responsible service." Its contents include news and media industry trends, analysis, professional ethics, and stories behind news. In October 2015, it was announced that the publishing frequency of the print magazine was being reduced from six to two issues per year in order to focus on its digital operations. Organization board The current chairman is Stephen J. Adler, previously editor-in-chief at Reuters from 2011 to 2021. The previous chairman of the magazine was Victor Navasky, a professor at the Columbia University Graduate School of Journalism and former editor and publisher of the poli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archimedes
Archimedes of Syracuse ( ; ) was an Ancient Greece, Ancient Greek Greek mathematics, mathematician, physicist, engineer, astronomer, and Invention, inventor from the ancient city of Syracuse, Sicily, Syracuse in History of Greek and Hellenistic Sicily, Sicily. Although few details of his life are known, based on his surviving work, he is considered one of the leading scientists in classical antiquity, and one of the greatest mathematicians of all time. Archimedes anticipated modern calculus and mathematical analysis, analysis by applying the concept of the Cavalieri's principle, infinitesimals and the method of exhaustion to derive and rigorously prove many geometry, geometrical theorem, theorems, including the area of a circle, the surface area and volume of a sphere, the area of an ellipse, the area under a parabola, the volume of a segment of a paraboloid of revolution, the volume of a segment of a hyperboloid of revolution, and the area of a spiral. Archimedes' other math ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courier Corporation
Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward and Blanche Cirker. It primarily reissues books that are out of print from their original publishers. These are often, but not always, books in the public domain. The original published editions may be scarce or historically significant. Dover republishes these books, making them available at a significantly reduced cost. Classic reprints Dover reprints classic works of literature, classical sheet music, and public-domain images from the 18th and 19th centuries. Dover also publishes an extensive collection of mathematical, scientific, and engineering texts. It often targets its reprints at a niche market, such as woodworking. Starting in 2015, the company branched out into graphic novel reprints, overseen by Dover acquisitions editor and former comics writer and editor Drew Ford. Most Dover reprints are photo facsimiles of the originals, retaining the original pagination a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lifting Boss
Lifting bosses or handling bosses are protrusions intentionally left on stones by masons to facilitate maneuvering the blocks with ropes and levers. They are an important feature of ancient and classical construction, and were often not cut away, despite having fulfilled their purpose. Sometimes this was the result of a cost-saving measure or a construction halt. Other times bosses were left as a stylistic element, and even if dressed back, a remnant of them was kept to make their existence obvious. File:Segesta BW 2012-10-10 17-15-12.JPG, Lifting bosses of the crepidoma (base) of the Segesta temple, Sicily File:Cusco_Piedra_de_los_doce_angulos.jpg, Levering bosses left on Inca walls of Cusco, Peru File:Propylées_Acropole_-_Athènes_(GRA1)_-_2022-03-26_-_18_(bosses).jpg, Bosses on the Propylaia (Acropolis of Athens) The Propylaia (, ; also spelled Propylaea) is the classical Greek Doric order, Doric building complex that functioned as the monumental ceremonial gateway to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Egyptian Technology
Ancient Egyptian technology describes devices and technologies invented or used in Ancient Egypt. The Egyptians invented and used many simple machines, such as the inclined plane, ramp and the lever, to aid construction processes. They used rope trusses to stiffen the beam (nautical), beam of ships. Egyptian paper, made from papyrus, and ancient Egyptian pottery, pottery were mass-produced and exported throughout the Mediterranean Basin. The wheel was used for a number of purposes, but chariots only came into use after the Second Intermediate Period. The Egyptians also played an important role in developing Mediterranean maritime history, maritime technology including ships and lighthouses. Technology in Dynastic Egypt Significant advances in ancient Egypt during the History of ancient Egypt, dynastic period include Egyptian astronomy, astronomy, Egyptian mathematics, mathematics, and Ancient Egyptian medicine, medicine. Their Egyptian geometry, geometry was a necessary outgrowth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
