Inverse-square law

In science, an inverse-square law is any scientific law stating that a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity. The fundamental cause for this can be understood as geometric dilution corresponding to point-source radiation into three-dimensional space. Radar energy expands during both the signal transmission and the reflected return, so the inverse square for both paths means that the radar will receive energy according to the inverse fourth power of the range. To prevent dilution of energy while propagating a signal, certain methods can be used such as a waveguide, which acts like a canal does for water, or how a gun barrel restricts hot gas expansion to one dimension in order to prevent loss of energy transfer to a bullet. Mathematically notated: intensity ∝ 1 distance 2 It can be mathematically expressed as: intensity 1 intensity 2 = distance 2 2 distance 1 2 or as the formulation of a constant quantity: intensity 1 × distance 1 2 = intensity 2 × distance 2 2 The divergence of a vector field, the resultant of radial inverse-square law fields with respect to one or more sources is everywhere proportional to the strength of the local sources, hence zero outside sources.

Newton's law of universal gravitation follows an inverse-square law, as do the effects of electric, light and radiation phenomena. The inverse-square law applies when some force, energy, or other conserved quantity is evenly radiated outward from a point source in three-dimensional space. Since the surface area of a sphere is proportional to the square of the radius, as the emitted radiation gets farther from the source, it is spread out over an area, increasing in proportion to the square of the distance from the source. Hence, the intensity of radiation passing through any unit area is inversely proportional to the square of the distance from the point source. Gauss's law is applicable, can be used with any physical quantity that acts in accordance with the inverse-square relationship. Gravitation is the attraction between objects. Newton's law states: The gravitational attraction force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation distance.

The force acts along the line joining them. If the distribution of matter in each body is spherically symmetric the objects can be treated as point masses without approximation, as shown in the shell theorem. Otherwise, if we want to calculate the attraction between massive bodies, we need to add all the point-point attraction forces vectorially and the net attraction might not be exact inverse square. However, if the separation between the massive bodies is much larger compared to their sizes to a good approximation, it is reasonable to treat the masses as a point mass located at the object's center of mass while calculating the gravitational force; as the law of gravitation, this law was suggested in 1645 by Ismael Bullialdus. But Bullialdus did not accept Kepler's second and third laws, nor did he appreciate Christiaan Huygens’s solution for circular motion. Indeed, Bullialdus maintained the sun's force was attractive at aphelion and repulsive at perihelion. Robert Hooke and Giovanni Alfonso Borelli both expounded gravitation in 1666 as an attractive force.

Hooke's 1670 Gresham lecture explained that gravitation applied to "all celestiall bodys" and added the principles that the gravitating power decreases with distance and that in the absence of any such power bodies move in straight lines. By 1679, Hooke thought gravitation had inverse square dependence and communicated this in a letter to Isaac Newton:my supposition is that the attraction always is in duplicate proportion to the distance from the center reciprocall. Hooke remained bitter about Newton claiming the invention of this principle though Newton's 1686 Principia acknowledged that Hooke, along with Wren and Halley, had separately appreciated the inverse square law in the solar system, as well as giving some credit to Bullialdus; the force of attraction or repulsion between two electrically charged particles, in addition to being directly proportional to the product of the electric charges, is inversely proportional to the square of the distance between them. The deviation of the exponent from 2 is less than one part in 1015.

F = kq1q2/r2 The intensity of light or other linear waves radiating from a point source is inversely proportional to the square of the distance from the source. More the irradiance

Ju Si-gyeong

Ju Si-gyeong was one of the founders of modern Korean linguistics. He was born in Hwanghae Province, he and his students helped standardize the Korean language, based spelling and grammar of the vernacular. He studied Classical Chinese from his childhood. After studying modern linguistics in Seoul, he established the Korean Language System Society in 1896, he hosted several seminars in the National Language Discussion Centre of the Sangdong Youth Academy of the Korean language. He proposed that the Korean parts of speech include nouns, adjectives, unconjugated adjectives, conjunction and sentence-final particles. In his 1914 publication, Sounds of the Language, he promotes writing Hangul linearly rather than syllabically; this is one of his few proposals not to have been implemented, although there have been experiments with linear hangul, most notably in Primorsky Krai. The National Language Classical Phonetics: based on his lecture notes An Introduction to the National Language An Introduction to the Chinese Language Sounds of the Language The Grammar of the National Language The History of the Downfall of Vietnam Ju Si-gyeong coined the name Hangul between 1910 and 1913 to identify the Korean writing system, which had existed under several other names such as onmun since the 15th century.

His name is sometimes written without the disambiguity hyphen: Chu Sigyong. In this case, they are mispronounced as Sig-yeong and Sig-yong respectively. List of Korea-related topics Korean language 주시경 a biography with a photo

Bentley Victoria Welfare F.C.

Bentley Victoria Welfare F. C. was an English football club based in Bentley, South Yorkshire. The club, formed as Bentley Victoria, was created after the dissolution of the previous senior team in the village, Bentley Colliery, they competed in the Doncaster & District Senior League before moving into the Yorkshire League in 1973. They won promotion from Division Three in their debut campaign before changing name to Bentley Victoria Welfare, they were relegated back to Division Three in 1976 but won promotion back at the first time of asking by winning the Third Division title, in 1978 they won their second successive promotion to reach the Yorkshire League's top flight. They were relegated back to Division Two in their first season but again bounced back to reach Division One again in 1980, they spent two further years in Division One before the Yorkshire League merged with the Midland League to form the Northern Counties East League. The club was placed in the Premier Division of the new competition's inaugural campaign, they stayed in the division for five years.

Throughout the 1970s and 1980s the club had competed in the FA Vase, reaching the 4th round in 1979. At the end of the 1986–87 season the club left the NCEL and disbanded, paving the way for the reformed Bentley Colliery to re-take their place as the senior team in the village. Players that have played in the Football League either before or after playing for Bentley Victoria Welfare – Paul Showler Paul Edmunds Jimmy Mann Rod Belfitt Mick Bates Best FA Vase performance: 4th Round, 1978–79