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Counterweight Trebuchet
A trebuchet () is a type of catapult that uses a hinged arm with a sling attached to the tip to launch a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than a traditional catapult. There are two main types of trebuchet. The first is the ''traction trebuchet'', or mangonel, which uses manpower to swing the arm. It first appeared in China by the 4th century BC. It spread westward, possibly via the Avars, and was adopted by the Byzantines, Persians, Arabs, and other neighboring peoples by the sixth to seventh centuries AD. The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century. "Although this is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Le Robert
Le Robert (; ) is a town and the third-largest commune in the French overseas department of Martinique. It is located in the northeastern (Atlantic) side of the island of Martinique. It contains the Sainte Rose-de-Lima church, Club Nautique Wind Force club, Stade Municipal du Robert and a sportsground. The village of Hyacinthe lies in the commune. Population Notable people * Édouard de Lépine (1932- 2020), historian and politician * Ronny Turiaf, NBA basketball player for the Los Angeles Clippers See also *Communes of the Martinique department The following is a list of the 34 communes of the Martinique overseas department of France. The communes cooperate in the following intercommunalities (as of 2025): References External links * Co ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Force
In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitude (mathematics), magnitude and Direction (geometry, geography), direction of a force are both important, force is a Euclidean vector, vector quantity. The SI unit of force is the newton (unit), newton (N), and force is often represented by the symbol . Force plays an important role in classical mechanics. The concept of force is central to all three of Newton's laws of motion. Types of forces often encountered in classical mechanics include Elasticity (physics), elastic, frictional, Normal force, contact or "normal" forces, and gravity, gravitational. The rotational version of force is torque, which produces angular acceleration, changes in the rotational speed of an object. In an extended body, each part applies forces on the adjacent pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sling (weapon)
A sling is a projectile weapon typically used to hand-throw a blunt projectile such as a stone, clay, or lead " sling-bullet". It is also known as the shepherd's sling or slingshot (in British English, although elsewhere it means something else). Someone who specializes in using slings is called a slinger. A sling has a small cradle or ''pouch'' in the middle of two retention cords, where a projectile is placed. There is a loop on the end of one side of the retention cords. Depending on the design of the sling, either the middle finger or the wrist is placed through a loop on the end of one cord, and a tab at the end of the other cord is placed between the thumb and forefinger. The sling is swung in an arc, and the tab released at a precise moment. This action releases the projectile to fly inertially and ballistically towards the target. By its double-pendulum kinetics, the sling enables stones (or spears) to be thrown much further than they could be by hand alone. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearing (mechanical), bearings or Bushing (bearing), bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type of axle is referred to as a ''spindle (tool), spindle''. Terminology On cars and trucks, several senses of the word ''axle'' occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. Strictly speaking, a shaft that rotates with the wheel, being either Bolt (fastener), bolted or rotating spline, splined in fixed relation to it, is called an ''axle'' or ''axle shaft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lever
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] |
Mechanical Advantage
Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for this is the ''law of the lever.'' Machine components designed to manage forces and movement in this way are called mechanisms. An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal machine does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take into account departures from the ideal. Levers The lever is a movable bar that pivots on a fulcrum attached to or positioned on or across a fixed point. The lever operates by applying forces at different distances from the fulcrum, or pivot. The location of the fulcrum deter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Machine
A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest 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 * Screw A simple machine uses a single applied force to do 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 elementary "building blocks" of which all more complicated machines (sometimes called "compound machines") are composed. For example, wheels, levers, and pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trebuchet2
A trebuchet () is a type of catapult that uses a hinged arm with a sling attached to the tip to launch a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than a traditional catapult. There are two main types of trebuchet. The first is the ''traction trebuchet'', or mangonel, which uses manpower to swing the arm. It first appeared in China by the 4th century BC. It spread westward, possibly via the Pannonian Avars, Avars, and was adopted by the Byzantine Empire, Byzantines, Persians, Arabs, and other neighboring peoples by the sixth to seventh centuries AD. The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onager (weapon)
The onager (, ; ) was a Roman torsion-powered siege engine. It is commonly depicted as a catapult with a bowl, bucket, or sling at the end of its throwing arm. The onager was first mentioned in 353 AD by Ammianus Marcellinus, who described onagers as the same as a scorpion. The onager is often confused with the later mangonel, a "traction trebuchet" that replaced torsion powered siege engines in the 6th century AD. Etymology According to two authors of the later Roman Empire who wrote on military affairs, the onager's name, meaning wild ass, derived from the kicking action of the machine that threw stones into the air. This action resembled the kicking action of the hooves of the wild ass, the Syrian wild ass, a subspecies of onager, which was native to the eastern part of the empire. In Latin this species was known as ''onagrum''. Design The onager consisted of a large frame placed horizontally on the ground with a vertical frame of solid timber rigidly fixed to its fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retronym
A retronym is a newer name for something that differentiates it from something else that is newer, similar, or seen in everyday life; thus, avoiding confusion between the two. Etymology The term ''retronym'', a neologism composed of the combining forms '' retro-'' (from Latin , "before") + '' -nym'' (from Greek , "name"), was coined by Frank Mankiewicz in 1980 and popularized by William Safire in '' The New York Times Magazine''. In 2000, '' The American Heritage Dictionary'' (4th edition) became the first major dictionary to include the word ''retronym''. Examples The global war from 1914 to 1918 was referred to at the time as the ''Great War''. However, after the subsequent global war erupted in 1939, the phrase ''Great War'' was gradually deprecated. The first came to be known as ''World War I'' and the second as ''World War II''. The first bicycles with two wheels of equal size were called " safety bicycles" because they were easier to handle than the then-dominant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
