Trajectories of three objects thrown at the same angle (70°). The black object does not experience any form of drag and moves along a parabola. The blue object experiencesStokes' drag, and the green objectNewtonian drag.
Ballistics is the field ofmechanics concerned with the launching,flight behaviour and impact effects ofprojectiles, especially weapon munitions such asbullets,unguided bombs,rockets and the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.
The oldest evidence of stone-tipped projectiles, which may or may not have been propelled by a bow (c.f.atlatl), dating to c. 280,000 years ago, were found in Ethiopia, present day East Africa.[1]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 ofHamburg. They had shallow grooves on the base, indicating that they were shot from a bow.[2] The oldest bow so far recovered is about 8,000 years old, found in theHolmegård swamp in Denmark.
The first devices identified as guns appeared inChina around 1000 AD, and by the 12th century the technology was spreading through the rest of Asia, and into Europe by the 13th century.[3]
After millennia of empirical development, the discipline of ballistics was initially studied and developed by Italian mathematicianNiccolò Tartaglia in 1531,[4][5] although he continued to use segments of straight-line motion, conventions established by the Greek philosopherAristotle andAlbert of Saxony, but with the innovation that he connected the straight lines by a circular arc.Galileo established the principle ofcompound motion in 1638,[6] using the principle to derive the parabolic form of the ballistic trajectory.[7] Ballistics was put on a solid scientific and mathematical basis byIsaac Newton, with the publication ofPhilosophiæ Naturalis Principia Mathematica in 1687. This gave mathematical laws of motion and gravity which for the first time made it possible to successfully predict trajectories.[citation needed]
The wordballistics comes from theGreekβάλλεινballein, meaning "to throw".
A projectile is any object projected intospace (empty or not) by the exertion of aforce. Although any object in motion through space (for example a thrownbaseball) is a projectile, the term most commonly refers to a weapon.[8][9] Mathematicalequations of motion are used to analyze projectiletrajectory.[citation needed]
Throwing is the launching of a projectile by hand. Although some other animals can throw, humans are unusually good throwers due to their high dexterity and good timing capabilities, and it is believed that this is an evolved trait. Evidence of human throwing dates back 2 million years.[11] The 90 mph throwing speed found in many athletes far exceeds the speed at whichchimpanzees can throw things, which is about 20 mph.[11] This ability reflects the ability of the humanshouldermuscles andtendons to storeelasticity until it is needed to propel an object.[11]
A sling is a projectileweapon typically used to throw a blunt projectile such as a stone, clay or lead "sling-bullet".
A sling has a small cradle orpouch in the middle of two lengths of cord. Thesling stone is placed in the pouch. The middle finger or thumb 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 frees the projectile to fly to the target.
A bow is a flexible piece of material which shoots aerodynamic projectiles calledarrows. The arrow is perhaps the first lethal projectile ever described in discussion of ballistics. A string joins the two ends and when the string is drawn back, the ends of the stick are flexed. When the string is released, the potential energy of the flexed stick is transformed into the velocity of the arrow.[12]Archery is the art or sport of shooting arrows from bows.[13]
A catapult is a device used to launch a projectile a great distance without the aid of explosive devices – particularly various types of ancient and medievalsiege engines.[14] The catapult has been used since ancient times, because it was proven to be one of the most effective mechanisms during warfare. The word "catapult" comes from theLatincatapulta, which in turn comes from theGreekκαταπέλτης (katapeltēs), itself fromκατά (kata), "against”[15] andπάλλω (pallō), "to toss, to hurl".[16][17] Catapults were invented by theancient Greeks.[18][19]
A gun is a normally tubular weapon or other device designed to discharge projectiles or other material.[20] The projectile may be solid, liquid, gas, or energy and may be free, as with bullets and artillery shells, or captive as withTaser probes andwhaling harpoons. The means of projection varies according to design but is usually effected by the action of gas pressure, either produced through the rapid combustion of apropellant or compressed and stored by mechanical means, operating on the projectile inside an open-ended tube in the fashion of a piston. The confined gas accelerates the movable projectile down the length of the tube imparting sufficient velocity to sustain the projectile's travel once the action of the gas ceases at the end of the tube or muzzle. Alternatively, acceleration via electromagnetic field generation may be employed in which case the tube may be dispensed with and a guide rail substituted.
A rocket is amissile,spacecraft,aircraft or othervehicle that obtainsthrust from arocket engine. Rocket engine exhaust is formed entirely from propellants carried within the rocket before use.[21] Rocket engines work byaction and reaction. Rocket engines push rockets forward simply by throwing their exhaust backwards extremely fast.
While comparatively inefficient for low speed use, rockets are relatively lightweight and powerful, capable of generating large accelerations and of attainingextremely high speeds with reasonable efficiency. Rockets are not reliant on the atmosphere and work very well in space.
Chemical rockets are the most common type of high performance rocket and they typically create their exhaust by the combustion ofrocket propellant. Chemical rockets store a large amount of energy in an easily released form, and can be very dangerous. However, careful design, testing, construction and use minimizes risks.
Ballistics can be studied usinghigh-speed photography orhigh-speed cameras. A photo of a Smith & Wesson revolver firing, taken with an ultra high speed air-gap flash. Using this sub-microsecond flash, the bullet can be imaged without motion blur.
Ballistics is often broken down into the following four categories:[23]
Internal ballistics the study of the processes originally accelerating projectiles
Transition ballistics the study of projectiles as they transition to unpowered flight
External ballistics the study of the passage of the projectile (thetrajectory) in flight
Terminal ballistics the study of the projectile and its effects as it ends its flight
Internal ballistics (also interior ballistics), a sub-field of ballistics, is the study of thepropulsion of aprojectile.
Inguns, internal ballistics covers the time from thepropellant's ignition until the projectile exits thegun barrel.[24] The study of internal ballistics is important todesigners and users of firearms of all types, from small-borerifles andpistols, to high-techartillery.
Forrocket propelled projectiles, internal ballistics covers the period during which arocket engine is providing thrust.[25]
Transitional ballistics, also known as intermediate ballistics,[26] is the study of a projectile's behavior from the time it leaves the muzzle until the pressure behind the projectile is equalized,[27] so it lies betweeninternal ballistics andexternal ballistics.
Terminal ballistics is the study of the behavior and effects of a projectile when it hits its target.[28]
Terminal ballistics is relevant both for small caliber projectiles as well as for large caliber projectiles (fired fromartillery). The study of extremely high velocity impacts is still very new and is as yet mostly applied tospacecraft design.
Forensic ballistics involves analysis of bullets and bullet impacts to determine information of use to a court or other part of a legal system. Separately from ballistics information, firearm and tool mark examinations ("ballistic fingerprinting") involve analyzing firearm, ammunition, and tool mark evidence in order to establish whether a certain firearm or tool was used in the commission of a crime.
US Army (February 1965),Interior Ballistics of Guns(PDF), Engineering Design Handbook: Ballistics Series, United States Army Materiel Command, AMCP 706-150, archived fromthe original(PDF) on September 24, 2020
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