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Clockwise
Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite sense of rotation or revolution is (in Commonwealth English) anticlockwise (ACW) or (in North American English) counterclockwise (CCW). Terminology Before clocks were commonplace, the terms " sunwise" and "deasil", "deiseil" and even "deocil" from the Scottish Gaelic language and from the same root as the Latin "dexter" ("right") were used for clockwise. " Widdershins" or "withershins" (from Middle Low German "weddersinnes", "opposite course") was used for counterclockwise. The terms clockwise and counterclockwise can only be applied to a rotational motion once a side of the rotational plane is specified, from which the rotation is observed. For example, the daily rotation of the Earth is clockwise when viewed from above the South Pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunwise
In Scottish folklore, sunwise, deosil or sunward (clockwise) was considered the “prosperous course”, turning from east to west in the direction of the sun. The opposite course, anticlockwise, was known as '' widdershins'' ( Lowland Scots), or ''tuathal'' (Scottish Gaelic). In the Northern Hemisphere, "sunwise" and "clockwise" run in the same direction, because sundials were used to tell time, and their features were transferred to clock faces. Another influence may have been the right-handed bias in many cultures. Irish culture During the days of Gaelic Ireland and of the Irish clans, the Psalter known as was used as botha rallying cry and protector in battle by the Chiefs of Clan O'Donnell. Before a battle it was customary for a chosen monk or holy man (usually attached to the Clan McGroarty and who was in a state of grace) to wear the Cathach and the cumdach, or book shrine, around his neck and then walk three times sunwise around the warriors of Clan O'Donnell. Stok ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to fasten materials by the engagement of the screw thread with a similar ''female thread'' (internal thread) in a matching part. Screws are often self-threading (also known as self-tapping) where the thread cuts into the material when the screw is turned, creating an internal thread that helps pull fastened materials together and prevents pull-out. There are many screws for a variety of materials; materials commonly fastened by screws include wood, sheet metal, and plastic. Explanation A screw is a combination of simple machines: it is, in essence, an inclined plane wrapped around a central shaft, but the inclined plane (thread) also comes to a sharp edge around the outside, which acts as a wedge as it pushes into the fastened material, and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Widdershins
Widdershins (sometimes withershins, widershins or widderschynnes) is a term meaning to go counter-clockwise, to go anti-clockwise, or to go lefthandwise, or to walk around an object by always keeping it on the left. Literally, it means to take a course opposite the apparent motion of the sun viewed from the Northern Hemisphere (the centre of this imaginary clock is the ground the viewer stands upon). The earliest recorded use of the word, as cited by the ''Oxford English Dictionary'', is in a 1513 translation of the ''Aeneid'', where it is found in the phrase "Abaisit I wolx, and widdersyns start my hair." In this sense, "widdershins start my hair" means "my hair stood on end". The use of the word also means "in a direction opposite to the usual" and "in a direction contrary to the apparent course of the sun". It is cognate with the German language ''widersinnig'', i.e., "against" + "sense". The term "widdershins" was especially common in Lowland Scots. The opposite of widders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation
Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional object has an infinite number of possible central axes and rotational directions. If the rotation axis passes internally through the body's own center of mass, then the body is said to be ''autorotating'' or '' spinning'', and the surface intersection of the axis can be called a '' pole''. A rotation around a completely external axis, e.g. the planet Earth around the Sun, is called ''revolving'' or ''orbiting'', typically when it is produced by gravity, and the ends of the rotation axis can be called the '' orbital poles''. Mathematics Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps a point fixed. This definition applies to rotations within both two and three dimensions (in a plane and in spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Judaism
Judaism ( he, ''Yahăḏūṯ'') is an Abrahamic, monotheistic, and ethnic religion comprising the collective religious, cultural, and legal tradition and civilization of the Jewish people. It has its roots as an organized religion in the Middle East during the Bronze Age. Modern Judaism evolved from Yahwism, the religion of ancient Israel and Judah, by the late 6th century BCE, and is thus considered to be one of the oldest monotheistic religions. Judaism is considered by religious Jews to be the expression of the covenant that God established with the Israelites, their ancestors. It encompasses a wide body of texts, practices, theological positions, and forms of organization. The Torah, as it is commonly understood by Jews, is part of the larger text known as the ''Tanakh''. The ''Tanakh'' is also known to secular scholars of religion as the Hebrew Bible, and to Christians as the "Old Testament". The Torah's supplemental oral tradition is represented by later tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right-hand Grip Rule
In mathematics and physics, the right-hand rule is a common mnemonic for understanding orientation of axes in three-dimensional space. It is also a convenient method for quickly finding the direction of a cross-product of 2 vectors. Most of the various left-hand and right-hand rules arise from the fact that the three axes of three-dimensional space have two possible orientations. One can see this by holding one's hands outward and together, palms up, with the thumbs out-stretched to the right and left, and the fingers making a curling motion from straight outward to pointing upward. (Note the picture to right is not an illustration of this.) The curling motion of the fingers represents a movement from the first (''x'' axis) to the second (''y'' axis); the third (''z'' axis) can point along either thumb. Left-hand and right-hand rules arise when dealing with coordinate axes. The rule can be used to find the direction of the magnetic field, rotation, spirals, electromagnetic field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right-hand Rule
In mathematics and physics, the right-hand rule is a common mnemonic for understanding orientation of axes in three-dimensional space. It is also a convenient method for quickly finding the direction of a cross-product of 2 vectors. Most of the various left-hand and right-hand rules arise from the fact that the three axes of three-dimensional space have two possible orientations. One can see this by holding one's hands outward and together, palms up, with the thumbs out-stretched to the right and left, and the fingers making a curling motion from straight outward to pointing upward. (Note the picture to right is not an illustration of this.) The curling motion of the fingers represents a movement from the first (''x'' axis) to the second (''y'' axis); the third (''z'' axis) can point along either thumb. Left-hand and right-hand rules arise when dealing with coordinate axes. The rule can be used to find the direction of the magnetic field, rotation, spirals, electromagnetic fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottle Cap
A bottle cap or bottle top is a closure for the top opening of a bottle. A cap is sometimes colourfully decorated with the logo of the brand of contents. Plastic caps are used for plastic bottles, while metal with plastic backing is used for glass; plastic caps are commonly made from PE or PP, whilst metal caps are usually either steel or aluminum. Plastic caps may have a pour spout. Flip-Top caps like Flapper closures provide controlled dispensing of dry products. Caps for plastic bottles are often made of a different type of plastic from the bottle. A cork is another type of closure for the top of a bottle. Types Caps were originally designed to be pressed over and around the top of a glass bottle to grab a small flange on the bottleneck. Crown cork The crown cork was patented by William Painter on February 2, 1892 (U.S. Patent 468,258). It had 24 teeth and a cork seal with a paper backing to prevent contact between the contents and the metal cap. The current versi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nut (hardware)
A nut is a type of fastener with a threaded hole. Nuts are almost always used in conjunction with a mating bolt to fasten multiple parts together. The two partners are kept together by a combination of their threads' friction (with slight elastic deformation), a slight stretching of the bolt, and compression of the parts to be held together. In applications where vibration or rotation may work a nut loose, various locking mechanisms may be employed: lock washers, jam nuts, eccentric double nuts, specialist adhesive thread-locking fluid such as Loctite, safety pins ( split pins) or lockwire in conjunction with castellated nuts, nylon inserts (nyloc nut), or slightly oval-shaped threads. Square nuts, as well as bolt heads, were the first shape made and used to be the most common largely because they were much easier to manufacture, especially by hand. While rare today due to the reasons stated below for the preference of hexagonal nuts, they are occasionally used in some situatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Paz, Bolivia
La Paz (), officially known as Nuestra Señora de La Paz (Spanish pronunciation: ), is the seat of government of the Plurinational State of Bolivia. With an estimated 816,044 residents as of 2020, La Paz is the third-most populous city in Bolivia. Its metropolitan area, which is formed by La Paz, El Alto, Achocalla, Viacha, and Mecapaca makes up the second most populous urban area in Bolivia, with a population of 2.0 million, after Santa Cruz de la Sierra with a population of 2.3 million. It is also the capital of the La Paz Department. The city, in west-central Bolivia southeast of Lake Titicaca, is set in a canyon created by the Choqueyapu River. It is in a bowl-like depression, part of the Amazon basin, surrounded by the high mountains of the Altiplano. Overlooking the city is the towering, triple-peaked Illimani. Its peaks are always snow-covered and can be seen from many parts of the city. At an elevation of roughly Above mean sea level, above sea level, L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plaza Murillo
The Plaza Murillo is the central plaza of the city of La Paz and the open space most connected to the political life of Bolivia. Prominent buildings on the plaza include the Presidential Palace, National Congress of Bolivia, and the Cathedral of La Paz (or more formally, the Cathedral Basilica of Our Lady of Peace, La Paz). It is located in the old town, or ''Casco Viejo'', of the city and is surrounded by Socabaya Street to the west, Ayacucho Street to the east, Comercio Street to the south, and a continuation of Ingavi and Ballivan Streets to the north. Names The Plaza was originally named the Plaza Mayor (''Greatest/Main Plaza'') after its construction. It was later known during the colonial period as the Plaza de Armas. Following independence, it was renamed the July 16 Plaza (Plaza 16 de Julio) on February 3, 1902, in honor of Pedro Murillo, captured and hung by Spanish troops in January 1810. History The plaza was designed in 1558 as part of the rectilinear grid of La Paz by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
