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Sling Shot
A slingshot is a small hand-powered projectile weapon. The classic form consists of a Y-shaped frame, with two natural rubber strips or tubes attached to the upper two ends. The other ends of the strips lead back to a pocket that holds the projectile. One hand holds the frame, while the other hand grasps the pocket and draws it back to the desired extent to provide power for the projectile—up to a full span of the arm with sufficiently long bands. Other names include catapult (United Kingdom), peashooter (United States), gulel (India), getis / guleli (Nepal), (South Africa), or ging, shanghai, pachoonga (Australia and New Zealand), Tirador (Philippines). Use and history Slingshots depend on strong Elasticity (physics), elastic materials, typically vulcanization, vulcanized natural rubber or the equivalent such as silicone rubber tubing, and thus date no earlier than the invention of vulcanized rubber by Charles Goodyear in 1839 (patented in 1844). By 1860, this "new engine" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slingshot (weapon)
A slingshot is a small hand-powered projectile weapon. The classic form consists of a Y-shaped frame, with two natural rubber strips or tubes attached to the upper two ends. The other ends of the strips lead back to a pocket that holds the projectile. One hand holds the frame, while the other hand grasps the pocket and draws it back to the desired extent to provide power for the projectile—up to a full span of the arm with sufficiently long bands. Other names include catapult (United Kingdom), peashooter (United States), gulel (India), getis / guleli (Nepal), (South Africa), or ging, shanghai, pachoonga (Australia and New Zealand), Tirador (Philippines). Use and history Slingshots depend on strong elastic materials, typically vulcanized natural rubber or the equivalent such as silicone rubber tubing, and thus date no earlier than the invention of vulcanized rubber by Charles Goodyear in 1839 (patented in 1844). By 1860, this "new engine" had established a reputation for use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolution Of Dignity
The Revolution of Dignity ( uk, Революція гідності, translit=Revoliutsiia hidnosti) also known as the Maidan Revolution or the Ukrainian Revolution,Ukraine profile - Timeline took place in in February 2014Everything you need to know about the Ukraine crisis [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Factors And Ergonomics
Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learning are to reduce human error, increase productivity, and enhance safety, system availability, and comfort with a specific focus on the interaction between the human and the engineered system. The field is a combination of numerous disciplines, such as psychology, sociology, engineering, biomechanics, industrial design, physiology, anthropometry, interaction design, visual design, user experience, and user interface design. Human factors research employs methods and approaches from these and other knowledge disciplines to study human behavior and generate data relevant to the four primary goals above. In studying and sharing learning on the design of equipment, devices, and processes that fit the human body and its cognitive abilities, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light sources. Modern day balloons are made from materials such as rubber, latex, polychloroprene, or a nylon fabric, and can come in many different colors. Some early balloons were made of dried animal bladders, such as the pig bladder. Some balloons are used for decorative purposes or entertaining purposes, while others are used for practical purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and low cost, have led to a wide range of applications. The rubber balloon was invented by Michael Faraday in 1824, during experiments with various gases. He invented them for use in the lab. Applications Play Decoration Balloons are used for decorating birthday par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angling
Angling is a fishing technique that uses a fish hook or "angle" (from Old English ''angol'') attached to a fishing line to tether individual fish in the mouth. The fishing line is usually manipulated via a fishing rod, although rodless techniques such as handlining and longlining also exist. Modern angling rods are usually fitted with a reel that functions as a cranking device for storing, retrieving and releasing out the line, although Tenkara fishing and cane pole fishing are two rod-angling methods that do not use any reel. The hook itself can be additionally weighted with a dense tackle called a sinker, and is typically dressed with an appetizing bait to attract the fish and enticing it into swallowing the hook, but sometimes an inedible fake bait with multiple attached hooks (known as a lure) is used instead of a single hook with edible bait. A bite indicator, such as a float or a quiver tip, is often used to relay underwater status of the hook to the surface. When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosin
Rosin (), also called colophony or Greek pitch ( la, links=no, pix graeca), is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term ''colophony'' comes from , Latin for "resin from Colophon" ( grc, Κολοφωνία ῥητίνη, Kolophōnia rhētinē), an ancient Ionic city. Properties Rosin is brittle and friable, with a faint piny odor. It is typically a glassy solid, though some rosins will form crystals, especially when brought into solution. The practical melting point varies with different specimens, some being semi-fluid at the temperature of boiling water, others melting at 100 °C to 120 °C. It is very flammable, burni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of the body. The concept originated with the studies by Archimedes of the usage of levers, which is reflected in his famous quote: "''Give me a lever and a place to stand and I will move the Earth''". Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object around a specific axis. Torque is defined as the product of the magnitude of the perpendicular component of the force and the distance of the line of action of a force from the point around which it is being determined. The law of conservation of energy can also be used to understand torque. The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbus, Nebraska
Columbus is a city in and the county seat of Platte County, in the state of Nebraska in the Midwestern United States. The population was 22,111 at the 2010 census. It is the 10th largest city in Nebraska, with 24,028 people as of the 2020 census. History Pre-settlement In the 18th century, the area around the confluence of the Platte and the Loup Rivers was used by a variety of Native American tribes, including Pawnee, Otoe, Ponca, and Omaha. The Pawnee are thought to have descended from the Protohistoric Lower Loup Culture; the Otoe had moved from central Iowa into the lower Platte Valley in the early 18th century; and the closely related Omaha and Ponca had moved from the vicinity of the Ohio River mouth, settling along the Missouri by the mid-18th century. In 1720, Pawnee and Otoe allied with the French massacred the Spanish force led by Pedro de Villasur just south of the present site of Columbus. In the 19th century, the "Great Platte River Road"—the valley of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Marino, California
San Marino is a residential city in Los Angeles County, California, United States. It was incorporated on April 25, 1913. At the 2010 census the population was 13,147. The city is one of the wealthiest places in the nation in terms of household income. By extension, with a median home price of $2,699,098, San Marino is one of the most expensive and exclusive neighborhoods in the Los Angeles area. History Origin of name The city takes its name from the ancient Republic of San Marino, founded by Saint Marinus who fled his home in Dalmatia (modern Croatia) at the time of the Diocletianic Persecution The Diocletianic or Great Persecution was the last and most severe persecution of Christians in the Roman Empire. In 303, the emperors Diocletian, Maximian, Galerius, and Constantius issued a series of edicts rescinding Christians' legal rights ... of Christians. Marinus took refuge at Monte Titano on the Italian peninsula, where he built a chapel and founded a monastic community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus
''Fraxinus'' (), common name, commonly called ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of usually medium to large trees, mostly deciduous, though a number of Subtropics, subtropical species are evergreen. The genus is widespread across much of Europe, Asia, and North America. The leaf, leaves are opposite leaves, opposite (rarely in Whorl (botany), whorls of three), and mostly pinnate, pinnately compound, though simple in a few species. The seeds, popularly known as "keys" or "helicopter seeds", are a type of fruit known as a samara (fruit), samara. Some ''Fraxinus'' species are Dioecy, dioecious, having male and female flowers on separate plants but sex in ash is expressed as a continuum between male and female individuals, dominated by unisexual trees. With age, ash may change their sexual function from predominantly male and hermaphrodite towards femaleness ; if grown as an ornamental and both sexes are present, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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