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The Ballistics (from Greek βάλλειν ''ballein'', "to throw") is the science of mechanics that deals with the launching, flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance. A ballistic body is a body with momentum which is free to move, subject to forces, such as the pressure of gases in a gun or a propulsive nozzle, by rifling in a barrel, by gravity, or by air drag. A ballistic missile is a missile only guided during the relatively brief initial powered phase of flight, whose trajectory is subsequently governed by the laws of classical mechanics, in contrast (for example) to a cruise missile which is aerodynamically guided in powered flight. == History and prehistory== The earliest known ballistic projectiles were stones and spears,〔("Archytas of Tar entum." ) ''Technology Museum of Thessaloniki, Macedonia, Greece/'' Retrieved: May 6, 2012.〕〔("Ancient history." ) ''Automata.'' Retrieved May 6, 2012.〕 and the throwing stick. The oldest evidence of stone-tipped projectiles, which may or may not have been propelled by a bow (c.f. atlatl), dating to c. 64,000 years ago, were found in Sibudu Cave, South Africa.〔Lyn Wadley from the University of the Witwatersrand (2010); (BBC: Oldest evidence of arrows found )〕 The oldest evidence of the use of bows to shoot arrows dates to about 10,000 years ago; it is based on pinewood arrows found in the Ahrensburg valley north of Hamburg. They had shallow grooves on the base, indicating that they were shot from a bow.〔McEwen E, Bergman R, Miller C. Early bow design and construction. Scientific American 1991 vol. 264 pp76-82.〕 The oldest bow so far recovered is about 8,000 years old, found in the Holmegård swamp in Denmark. Archery seems to have arrived in the Americas with the Arctic small tool tradition, about 4,500 years ago. The first devices identified as guns appeared in China around 1000 AD, and by the 12th century the technology was spreading through the rest of Asia, and into Europe by the 13th century.〔(Judith Herbst, The History Of Weapons, Lerner Publications, 2005, page 8 )〕 After millennia of empirical development, the discipline of ballistics was initially studied and developed by Italian mathematician Niccolo Tartaglia in 1531 〔Ballistics in the Seventeenth Century: A Study in the Relations of Science and War with Reference Principally to England,CUP Archive - 1952, page 36〕〔Niccolo' Tartaglia, Nova Scientia, 1537. (a treatise on gunnery and ballistics).〕 and went on to be put on a solid scientific and mathematical basis with the publication of Philosophiæ Naturalis Principia Mathematica in 1687 which gave mathematical laws of motion and gravity which for the first time made it possible to successfully predict trajectories. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ballistics」の詳細全文を読む スポンサード リンク
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