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Bow (archery)
The bow and arrow is a ranged weapon system consisting of an elastic launching device (bow) and long-shafted projectiles (arrows). Humans used bows and arrows for hunting and aggression long before recorded history, and the practice was common to many prehistoric cultures. They were important weapons of war from ancient history until the early modern period, where they were rendered increasingly obsolete by the development of the more powerful and accurate firearms. Today, bows and arrows are mostly used for hunting and sports. Archery is the art, practice, or skill of using bows to shoot arrows.Paterson ''Encyclopaedia of Archery'' p. 17 A person who shoots arrows with a bow is called a bowman or an archer. Someone who makes bows is known as a bowyer,Paterson ''Encyclopaedia of Archery'' p. 31 someone who makes arrows is a fletcher,Paterson ''Encyclopaedia of Archery'' p. 56 and someone who manufactures metal arrowheads is an arrowsmith.Paterson ''Encyclopaedia of Archery'' p. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guinea Fowl Hunter (49109425873)
Guinea ( ),, fuf, 𞤘𞤭𞤲𞤫, italic=no, Gine, wo, Gine, nqo, ߖߌ߬ߣߍ߫, bm, Gine officially the Republic of Guinea (french: République de Guinée), is a coastal country in West Africa. It borders the Atlantic Ocean to the west, Guinea-Bissau to the northwest, Senegal to the north, Mali to the northeast, Cote d'Ivoire to the southeast, and Sierra Leone and Liberia to the south. It is sometimes referred to as Guinea-Conakry after its capital Conakry, to distinguish it from other territories in the eponymous region such as Guinea-Bissau and Equatorial Guinea. It has a population of million and an area of . Formerly French Guinea, it achieved independence in 1958. It has a history of military coups d'état.Nicholas Bariyo & Benoit FauconMilitary Faction Stages Coup in Mineral-Rich Guinea ''Wall Street Journal'' (September 5, 2021).Krista LarsonEXPLAINER: Why is history repeating itself in Guinea's coup? Associated Press (September 7, 2021).Danielle Paquet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowyer
A bowyer is a master-craftsman who makes bows. Though this was once a widespread profession, the importance of bowyers and of bows was diminished by the introduction of gunpowder weaponry. However, the trade has survived and many bowyers continue to produce high-end bows. History Historically, a wide variety of bows have been produced for purposes ranging from food gathering and warfare to recreation. Who created these bows depended mainly on the type of bow being produced, but also on the quantity required. The skills required tend to divide traditional bowyers into two groups: Makers of self bows In clans or social groups that used wooden self bows (bows made entirely from one piece of wood) bows would sometimes be crafted by the individual user; however, even with fairly simple bow designs it was often easier to rely upon a few skilled bowyers within the group. By working in groups more could be accomplished. In medieval England, for example, professional bowyers produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest. Formally, a kinetic energy is any term in a system's Lagrangian which includes a derivative with respect to time. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2. In relativistic mechanics, this is a good approximation only when ''v'' is much less than the speed of light. The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Shooting
Point shooting, also known as target- or threat-focused shooting, intuitive shooting, instinctive shooting or subconscious tactical shooting, is a practical shooting method where the shooter points a ranged weapon (typically a revolver or semiautomatic pistol) at a target without relying on the use of sights to aim. Emphasis is placed on fast draw and trying to score preemptive hits first. In close quarters combat, where life-threatening situations emerge very quickly, sighted marksmanship techniques become risky, so advocates of point shooting emphasize a less sighting-oriented style that prioritizes the tactical advantages of quick fire superiority and suppression. Point shooting is also a technique used by trained archers and marksmen to improve general accuracy when using a bow, crossbow, firearm or other ranged weapon. By developing a muscle memory for a given weapon, the shooter can become so accustomed to the weapon's weight and balance in its typical shooting position a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Energy
Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed, stretched or generally deformed in any manner. Elasticity theory primarily develops formalisms for the mechanics of solid bodies and materials. (Note however, the work done by a stretched rubber band is not an example of elastic energy. It is an example of entropic elasticity.) The elastic potential energy equation is used in calculations of positions of mechanical equilibrium. The energy is potential as it will be converted into other forms of energy, such as kinetic energy and sound energy, when the object is allowed to return to its original shape (reformation) by its elasticity. U = \frac 1 2 k\, \Delta x^2 The essence of elasticity is reversibility. Forces applied to an elastic material transfer energy into the material which, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (device)
A spring is an elastic object that stores mechanical energy. In everyday use the term often refers to coil springs, but there are many different spring designs. Modern springs are typically manufactured from spring steel, although some non-metallic objects like the bow are also springs. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The ''rate'' or ''spring constant'' of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve. An extension or compression spring's rate is expressed in units of force divided by distance, for example or N/m or lbf/in. A torsion spring is a spring that works by twisting; when it is twisted about its axis by an angle, it produces a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominant Hand
In human biology, handedness is an individual's preferential use of one hand, known as the dominant hand, due to it being stronger, faster or more dextrous. The other hand, comparatively often the weaker, less dextrous or simply less subjectively preferred, is called the non-dominant hand. In a study from 1975 on 7688 children in US grades 1-6, Left handers comprised 9.6% of the sample, with 10.5% of male children and 8.7% of female children being left-handed. Handedness is often defined by one's writing hand, as it is fairly common for people to prefer to do some tasks with each hand. There are examples of true ambidexterity (equal preference of either hand), but it is rare—most people prefer using one hand for most purposes. Most of the current research suggests that left-handedness has an epigenetic marker—a combination of genetics, biology and the environment. Because the vast majority of the population is right-handed, many devices are designed for use by right-hande ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow Draw
A bow draw is the method used to draw a bow. Currently, the most common method in modern target archery is the Mediterranean draw, long the usual method in European archery. Other methods include the pinch draw and the Mongolian or "thumb" draw. In traditional archery practice outside of Western Europe the variations of the thumb draw are by far the most dominant draw types with the Mediterranean draw restricted to Olympic style of target shooting. Pinch draw and release The pinch draw squeezes the end of the arrow between the thumb and index finger. Most people use this draw naturally when they first start shooting. This is often called the "primary draw/release"; the advantage of this draw is that the release is very clean; when the pull reaches a certain point, friction can no longer hold the arrow and it flies free. However, this release prevents the drawing of a stiff bow unless the archer possesses enormous strength in the fingers. It is now of historical interest, but was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nock (arrow)
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers called fletchings mounted near the rear, and a slot at the rear end called a nock for engaging the bowstring. A container or bag carrying additional arrows for convenient reloading is called a quiver. The use of bows and arrows by humans predates recorded history and is common to most cultures. A craftsman who makes arrows is a fletcher, and one that makes arrowheads is an arrowsmith.Paterson ''Encyclopaedia of Archery'' p. 56 History The oldest evidence of likely arrowheads, dating to c. 64,000 years ago, were found in Sibudu Cave, current South Africa.Backwell L, d'Errico F, Wadley L.(2008). Middle Stone Age bone tools from the Howiesons Poort layers, Sibudu Cave, South Africa. Journal of Archaeological Science, 35:1566–1580. Backwel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowstring
A bowstring joins the two ends of the bow stave and launches the arrow. Desirable properties include light weight, strength, resistance to abrasion, and resistance to water. Mass has most effect at the center of the string; of extra mass in the middle of the string slows the arrow about as much as at the ends. String forms Most bowstrings may be described as either simple, reverse-twisted, or looped. Simple strings may be made of any fiber, twisted into a single cord. Such strings have been used in many parts of the world and are still effective and fairly quick to make. However, they tend to be weaker for their weight, and they may also come apart if not kept constantly under tension. They are normally secured to the bow by a knot/round turn and two half-hitches at each end. Reverse-twisted strings are traditional in Europe and North America for most natural materials. Linen and hemp fiber have been widely used. The form is also used for modern materials. A reverse-twisted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc (geometry)
In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that appeared more than 2000 years ago in Euclid's ''Elements'': "The urvedline is the first species of quantity, which has only one dimension, namely length, without any width nor depth, and is nothing else than the flow or run of the point which will leave from its imaginary moving some vestige in length, exempt of any width." This definition of a curve has been formalized in modern mathematics as: ''A curve is the image of an interval to a topological space by a continuous function''. In some contexts, the function that defines the curve is called a ''parametrization'', and the curve is a parametric curve. In this article, these curves are sometimes called ''topological curves'' to distinguish them from more constrained curves such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stiffness
Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single degree of freedom (DOF) (for example, stretching or compression of a rod), the stiffness is defined as k = \frac where, * F is the force on the body * \delta is the displacement produced by the force along the same degree of freedom (for instance, the change in length of a stretched spring) In the International System of Units, stiffness is typically measured in newtons per meter (N/m). In Imperial units, stiffness is typically measured in pounds (lbs) per inch. Generally speaking, deflections (or motions) of an infinitesimal element (which is viewed as a point) in an elastic body can occur along multiple DOF (maximum of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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