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Football Field (area)
An unusual unit of measurement is a unit of measurement that does not form part of a coherent system of measurement, especially because its exact quantity may not be well known or because it may be an inconvenient multiple or fraction of a base unit. This definition is not exact since it includes units such as the ''week'' or the ''light-year'', which are quite "usual" in the sense that they are often used, but can be "unusual" if taken out of their common context, as demonstrated by the furlong-firkin-fortnight (FFF) system of units. Many of the unusual units of measurements listed here are colloquial measurements, units devised to compare a measurement to common and familiar objects. Length Hammer unit Valve's Source game engine uses the ''Hammer unit'' as its base unit of length. This unit refers to Source's official map creation software, Hammer. The exact definition varies from game to game, but a Hammer unit is usually defined as a sixteenth of a foot (16 Hamm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systems Of Measurement
A system of measurement is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Systems of measurement in use include the International System of Units or (the modern form of the metric system), the British imperial system, and the United States customary system. History The French Revolution gave rise to the metric system, and this has spread around the world, replacing most customary units of measure. In most systems, length (distance), mass, and time are ''base quantities''. Later science developments showed that an electromagnetic quantity such as electric charge or electric current could be added to extend the set of base quantities. Gaussian units have only length, mass, and time as base quantities, with no separate electromagnetic dimension. Other quantities, such as power and speed, are derived from the base set: for example ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eight (rowing)
An eight is a rowing boat used in the sport of competitive rowing (crew). It is designed for eight rowers, who propel the boat with sweep oars, and is steered by a coxswain, or "cox". Each of the eight rowers has one oar. The rowers, who sit in a line in the centre of the boat and facing the stern, are usually placed alternately, with four on the port side (rower's right hand side - also traditionally known as "stroke side") and four on the starboard side (rower's lefthand side - known as "bow side"). The cox steers the boat using a rudder and is normally seated at the stern of the boat. Because of the speed of the boat, it is generally considered unsafe to row coxless or to have a bowloader cox. Racing boats (often called "shells") are long, narrow, and broadly semi-circular in cross-section in order to reduce drag to a minimum. Originally made from wood, shells are now almost always made from a composite material (usually carbon-fibre reinforced plastic) for strengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits the Sun, from a maximum ( aphelion) to a minimum ( perihelion) and back again once each year. The astronomical unit was originally conceived as the average of Earth's aphelion and perihelion; however, since 2012 it has been defined as exactly (see below for several conversions). The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the ast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Radius
Earth radius (denoted as ''R''🜨 or R_E) is the distance from the center of Earth to a point on or near its surface. Approximating the figure of Earth by an Earth spheroid, the radius ranges from a maximum of nearly (equatorial radius, denoted ''a'') to a minimum of nearly (polar radius, denoted ''b''). A ''nominal Earth radius'' is sometimes used as a unit of measurement in astronomy and geophysics, which is recommended by the International Astronomical Union to be the equatorial value. A globally-average value is usually considered to be with a 0.3% variability (±10 km) for the following reasons. The International Union of Geodesy and Geophysics (IUGG) provides three reference values: the ''mean radius'' (R) of three radii measured at two equator points and a pole; the ''authalic radius'', which is the radius of a sphere with the same surface area (R); and the ''volumetric radius'', which is the radius of a sphere having the same volume as the ellipsoid (R). All thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-second
The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly . Just as the second forms the basis for other units of time, the light-second can form the basis for other units of length, ranging from the light-nanosecond ( or just under one international foot) to the light-minute, light-hour and light-day, which are sometimes used in popular science publications. The more commonly used light-year is also currently defined to be equal to precisely , since the definition of a year is based on a Julian year (not the Gregorian year) of exactly 365.25 days, each of exactly SI seconds. Use in telecommunications Communications signals on Earth rarely travel at precisely the speed of light in free space. Distances in fractions of a light-second are useful for planning telecommunications networks. * One light-nanosecond is almost 300 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Distance (astronomy)
The instantaneous Earth–Moon distance, or distance to the Moon, is the distance from the center of Earth to the center of the Moon. Lunar distance (LD or \Delta_), or Earth–Moon characteristic distance, is a unit of measure in astronomy. More technically, it is the semi-major axis of the geocentric lunar orbit. The lunar distance is on average approximately , or 1.28 light-seconds; this is roughly 30 times Earth's diameter or 9.5 times Earth's circumference. A little less than 400 lunar distances make up an astronomical unit. The semi-major axis has a value of . The time-averaged distance between the centers of Earth and the Moon is . The actual distance varies over the course of the orbit of the Moon, from at the perigee to at apogee, resulting in a differential range of . Lunar distance is commonly used to express the distance to near-Earth object encounters. Lunar semi-major axis is an important astronomical datum; the few millimeter precision of the range measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxicab Geometry
A taxicab geometry or a Manhattan geometry is a geometry whose usual distance function or metric of Euclidean geometry is replaced by a new metric in which the distance between two points is the sum of the absolute differences of their Cartesian coordinates. The taxicab metric is also known as rectilinear distance, ''L''1 distance, ''L''1 distance or \ell_1 norm (see ''Lp'' space), snake distance, city block distance, Manhattan distance or Manhattan length. The latter names refer to the rectilinear street layout on the island of Manhattan, where the shortest path a taxi travels between two points is the sum of the absolute values of distances that it travels on avenues and on streets. The geometry has been used in regression analysis since the 18th century, and is often referred to as LASSO. The geometric interpretation dates to non-Euclidean geometry of the 19th century and is due to Hermann Minkowski. In \mathbb^2 , the taxicab distance between two points (x_1, y_1) and (x_2, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan
Manhattan (), known regionally as the City, is the most densely populated and geographically smallest of the five Boroughs of New York City, boroughs of New York City. The borough is also coextensive with New York County, one of the List of counties in New York, original counties of the U.S. state of New York (state), New York. Located near the southern tip of New York State, Manhattan is based in the Eastern Time Zone and constitutes both the geographical and demographic center of the Northeast megalopolis and the urban core of the New York metropolitan area, the largest metropolitan area in the world by urban area, urban landmass. Over 58 million people live within 250 miles of Manhattan, which serves as New York City’s economic and administrative center, cultural identifier, and the city’s historical birthplace. Manhattan has been described as the cultural, financial, Media in New York City, media, and show business, entertainment capital of the world, is considered a saf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
City Block
A city block, residential block, urban block, or simply block is a central element of urban planning and urban design. A city block is the smallest group of buildings that is surrounded by streets, not counting any type of thoroughfare within the area of a building or comparable structure. City blocks are the space for buildings within the street pattern of a city, and form the basic unit of a city's urban fabric. City blocks may be subdivided into any number of smaller land lots usually in private ownership, though in some cases, it may be other forms of tenure. City blocks are usually built-up to varying degrees and thus form the physical containers or "streetwalls" of public space. Most cities are composed of a greater or lesser variety of sizes and shapes of urban block. For example, many pre-industrial cores of cities in Europe, Asia, and the Middle East tend to have irregularly shaped street patterns and urban blocks, while cities based on grids have much more regular arr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Football Field
Canadian football () is a sport played in Canada in which two teams of 12 players each compete for territorial control of a field of play long and wide attempting to advance a pointed oval-shaped ball into the opposing team's scoring area (end zone). In Canada, ''football'' may refer to Canadian football and American football collectively, or to either sport specifically, depending on context. Outside of Canada, the term Canadian football is used exclusively to describe this sport, even in the United States; the term ''gridiron football'' (or, more rarely, ''North American football'') is also used worldwide as well to refer to both sports collectively. The two sports have shared origins and are closely related but have some key differences. With the probable exception of a few minor and recent changes, for which there is circumstantial evidence to suggest the existence of at least informal cross-border collaboration, the modern rules of the two sports evolved independently. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UEFA Champions League
The UEFA Champions League (abbreviated as UCL, or sometimes, UEFA CL) is an annual club football competition organised by the Union of European Football Associations (UEFA) and contested by top-division European clubs, deciding the competition winners through a round robin group stage to qualify for a double-legged knockout format, and a single leg final. It is one of the most prestigious football tournaments in the world and the most prestigious club competition in European football, played by the national league champions (and, for some nations, one or more runners-up) of their national associations. Introduced in 1955 as the (French for European Champion Clubs' Cup), and commonly known as the European Cup, it was initially a straight knockout tournament open only to the champions of Europe's domestic leagues, with its winner reckoned as the European club champion. The competition took on its current name in 1992, adding a round-robin group stage in 1991 and allowing mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Football Pitch
A football pitch (also known as soccer field) is the playing surface for the game of association football. Its dimensions and markings are defined by Law 1 of the Laws of the Game, "The Field of Play". The pitch is typically made of natural turf or artificial turf, although amateur and recreational teams often play on dirt fields. Artificial surfaces are allowed only to be green in colour. All line markings on the pitch form part of the area which they define. For example, a ball on or above the touchline is still on the field of play, and a foul committed over the line bounding the penalty area results in a penalty. Therefore, a ball has to completely cross the touchline to be out of play, and a ball has to wholly cross the goal line (between the goal posts) in order for a goal to be scored; if any part of the ball is still on or above the line, a goal is not scored and the ball is still in play. The field descriptions that apply to adult matches are described below. Bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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