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System 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, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Units Of Measurement
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity. The metre (symbol m) is a unit of length that represents a definite predetermined length. For instance, when referencing "10 metres" (or 10 m), what is actually meant is 10 times the definite predetermined length called "metre". The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to the present. A multitude of systems of units used to be very common. Now there is a global standard, the International System of Units (SI), the modern form of the metric system. In trade, weights and measures is often a subject of governmental regulation, to ensure fairness and transparency. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yards
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.9144 meter. A distance of 1,760 yards is equal to 1 mile. The US survey yard is very slightly longer. Name The term, ''yard'' derives from the Old English , etc., which was used for branches, staves and measuring rods. It is first attested in the late 7th century laws of Ine of Wessex, where the "yard of land" mentioned is the yardland, an old English unit of tax assessment equal to hide. Around the same time the Lindisfarne Gospels account of the messengers from John the Baptist in the Gospel of Matthew used it for a branch swayed by the wind. In addition to the yardland, Old and Middle English both used their forms of "yard" to denote the surveying lengths of or , used in computing acres, a distance now usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Customary Units
United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English units which were in use in the British Empire before the U.S. became an independent country. The United Kingdom's system of measures was overhauled in 1824 to create the imperial system, which was officially adopted in 1826, changing the definitions of some of its units. Consequently, while many U.S. units are essentially similar to their imperial counterparts, there are significant differences between the systems. The majority of U.S. customary units were redefined in terms of the meter and kilogram with the Mendenhall Order of 1893 and, in practice, for many years before. T.C. Mendenhall, Superintendent of Standard Weights and MeasuresOrder of April 5, 1893, published as Appendix 6 to the Report for 1893 of the United States Coast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre ( British spelling) or meter ( American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefixed forms are also used relatively frequently. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in of a second. After the 2019 redefini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton's Laws Of Motion
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows: # A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force. # When a body is acted upon by a force, the time rate of change of its momentum equals the force. # If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his '' Philosophiæ Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy''), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics. In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yard
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.9144 meter. A distance of 1,760 yards is equal to 1 mile. The US survey yard is very slightly longer. Name The term, ''yard'' derives from the Old English , etc., which was used for branches, staves and measuring rods. It is first attested in the late 7th century laws of Ine of Wessex, where the "yard of land" mentioned is the yardland, an old English unit of tax assessment equal to hide. Around the same time the Lindisfarne Gospels account of the messengers from John the Baptist in the Gospel of Matthew used it for a branch swayed by the wind. In addition to the yardland, Old and Middle English both used their forms of "yard" to denote the surveying lengths of or , used in computing acres, a distance now usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubit
The cubit is an ancient unit of length based on the distance from the elbow to the tip of the middle finger. It was primarily associated with the Sumerians, Egyptians, and Israelites. The term ''cubit'' is found in the Bible regarding Noah's Ark, Ark of the Covenant, Tabernacle, Solomon's Temple. The ''common cubit'' was divided into 6 palms × 4 fingers = 24 digits. ''Royal cubits'' added a palm for 7 palms × 4 fingers = 28 digits. These lengths typically ranged from , with an ancient Roman cubit being as long as . Cubits of various lengths were employed in many parts of the world in antiquity, during the Middle Ages and as recently as early modern times. The term is still used in hedgelaying, the length of the forearm being frequently used to determine the interval between stakes placed within the hedge. Etymology The English word "cubit" comes from the Latin noun "elbow", from the verb "to lie down", from which also comes the adjective " recumbent". Ancie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
League (unit)
A league is a unit of length. It was common in Europe and Latin America, but is no longer an official unit in any nation. Derived from an ancient Celtic unit and adopted by the Romans as the ''leuga'', the league became a common unit of measurement throughout western Europe. It may have originally represented, roughly, the distance a person could walk in an hour. Since the Middle Ages, many values have been specified in several countries. Different definitions Ancient Rome The league was used in Ancient Rome, defined as 1½ Roman miles (7,500 Roman feet, modern 2.2 km or 1.4 miles). The origin is the ''leuga Gallica'' ''(also: leuca Callica)'', the league of Gaul. Argentina The Argentine league (''legua'') is or 6,666 ''varas'': 1 ''vara'' is . English-speaking world On land, the league is most commonly defined as three miles (4.83km), though the length of a mile could vary from place to place and depending on the era. At sea, a league is . English usage a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadia (length)
The stadion (plural stadia, grc-gre, ; latinized as stadium), also anglicized as stade, was an ancient Greek unit of length, consisting of 600 Ancient Greek feet (''podes''). Calculations According to Herodotus, one stadium was equal to 600 Greek feet (''podes''). However, the length of the foot varied in different parts of the Greek world, and the length of the stadion has been the subject of argument and hypothesis for hundreds of years. An empirical determination of the length of the stadion was made by Lev Vasilevich Firsov, who compared 81 distances given by Eratosthenes and Strabo with the straight-line distances measured by modern methods, and averaged the results. He obtained a result of about . Various equivalent lengths have been proposed, and some have been named. Among them are: Which measure of the stadion is used can affect the interpretation of ancient texts. For example, the error in the calculation of Earth's circumference by Eratosthenes or Posido ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Mile
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute ( of a degree) of latitude. Today the international nautical mile is defined as exactly . The derived unit of speed is the knot, one nautical mile per hour. Unit symbol There is no single internationally agreed symbol, with several symbols in use. * M is used as the abbreviation for the nautical mile by the International Hydrographic Organization. * NM is used by the International Civil Aviation Organization. * nmi is used by the Institute of Electrical and Electronics Engineers and the United States Government Publishing Office. * nm is a non-standard abbreviation used in many maritime applications and texts, including U.S. Government Coast Pilots and Sailing Directions. It conflicts with the SI symbol for nanometre. History The word mile is from the Latin wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mile
The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 English feet, or 1,760 yards. The statute mile was standardised between the British Commonwealth and the United States by an international agreement in 1959, when it was formally redefined with respect to SI units as exactly . With qualifiers, ''mile'' is also used to describe or translate a wide range of units derived from or roughly equivalent to the Roman mile, such as the nautical mile (now exactly), the Italian mile (roughly ), and the Chinese mile (now exactly). The Romans divided their mile into 5,000 Roman feet but the greater importance of furlongs in Elizabethan-era England meant that the statute mile was made equivalent to or in 1593. This form of the mile then spread across the British Empire, some successor states of whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furlong
A furlong is a measure of distance in imperial units and United States customary units equal to one eighth of a mile, equivalent to 660 feet, 220 yards, 40 rods, 10 chains or approximately 201 metres. It is now mostly confined to use in horse racing, where in many countries it is the standard measurement of race lengths, and agriculture, where is it used to measure rural field lengths and distances. In the United States, some states use older definitions for surveying purposes, leading to variations in the length of the furlong of two parts per million, or about . This variation is too small to have practical consequences in most applications. Using the international definition of the yard as exactly 0.9144 metres, one furlong is 201.168 metres, and five furlongs are about 1 kilometre ( exactly). History The name ''furlong'' derives from the Old English words ' (furrow) and ' (long). Dating back at least to early Anglo-Saxon times, it originally referred to the length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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