:Projectile

{{See also|Projectile motion}}

File:Schwerer Gustav projectile 2.jpg Schwerer Gustav artillery piece. Most projectile weapons use the compression or expansion of gases as their motive force.]]

Blowguns and pneumatic rifles use compressed gases, while most other guns and cannons utilize expanding gases liberated by sudden chemical reactions by propellants like smokeless powder. Light-gas guns use a combination of these mechanisms.

Railguns utilize electromagnetic fields to provide acceleration along the entire length of the device, greatly increasing the muzzle velocity.

Some projectiles provide propulsion during flight by means of a rocket engine or jet engine. In military terminology, a rocket is unguided, while a missile is guided. Note the two meanings of "rocket" (weapon and engine): an ICBM is a guided missile with a rocket engine.

An explosion, whether or not by a weapon, causes the debris to act as multiple high velocity projectiles. An explosive weapon or device may also be designed to produce many high velocity projectiles by the break-up of its casing; these are correctly termed fragments.

Image:baseball.jpg.{{cite news|url=http://www.boston.com/sports/blogs/thebuzz/2010/08/aroldis_chapman.html|title=Aroldis Chapman hits 105 mph|publisher=Boston.com|date=2010-08-26|access-date=2010-08-30|first=Matt|last=Pepin|archive-url=https://web.archive.org/web/20100831185316/http://www.boston.com/sports/blogs/thebuzz/2010/08/aroldis_chapman.html|archive-date=31 August 2010 |url-status=live}}

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In projectile motion the most important force applied to the projectile mass is the propelling force. In many sports, the propelling forces are provided by muscles that accelerate the projectile (ball, disc, javelin, hammer, dart), and the stronger the propelling force, the faster and farther the projectile will travel. See pitching, bowling.

Many projectiles, e.g. shells, may carry an explosive charge or another chemical or biological substance. Aside from explosive payload, a projectile can be designed to cause special damage, e.g. fire (see also early thermal weapons), or poisoning (see also arrow poison).

{{excerpt|Kinetic energy weapon}}

Some projectiles stay connected by a cable to the launch equipment after launching it:

• for guidance: wire-guided missile (range up to {{convert|4000|m|disp=or|||}})
• to administer an electric shock, as in the case of a Taser (range up to {{convert|10.6|m|disp=or|||}}); two projectiles are shot simultaneously, each with a cable.
• to make a connection with the target, either to tow it towards the launcher, as with a whaling harpoon, or to draw the launcher to the target, as a grappling hook does.

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{{See also|Orders of magnitude (speed)|Muzzle velocity}}

{{main|Projectile motion}}

An object projected at an angle to the horizontal has both the vertical and horizontal components of velocity. The vertical component of the velocity on the y-axis is given as $V\_y=U\backslash sin\backslash theta$ while the horizontal component of the velocity is $V\_x=U\backslash cos\backslash theta$. There are various calculations for projectiles at a specific angle $\backslash theta$:

1. Time to reach maximum height. It is symbolized as ($t$), which is the time taken for the projectile to reach the maximum height from the plane of projection. Mathematically, it is given as $t=U\; \backslash sin\backslash theta/g$ where $g$ = acceleration due to gravity (app 9.81 m/s²), $U$ = initial velocity (m/s) and $\backslash theta$ = angle made by the projectile with the horizontal axis.

2. Time of flight ($T$): this is the total time taken for the projectile to fall back to the same plane from which it was projected. Mathematically it is given as $T=2U\backslash sin\backslash theta/g$.

3. Maximum Height ($H$): this is the maximum height attained by the projectile OR the maximum displacement on the vertical axis (y-axis) covered by the projectile. It is given as $H\; =\; U^2\; \backslash sin^2\backslash theta/2g$.

4. Range ($R$): The Range of a projectile is the horizontal distance covered (on the x-axis) by the projectile. Mathematically, $R\; =\; U^2\; \backslash sin\; 2\backslash theta/g$. The Range is maximum when angle $\backslash theta$ = 45°, i.e. $\backslash sin\; 2\backslash theta=1$.

• Atlatl
• Ballistics
• Gunpowder
• Bullet
• Impact depth
• Kinetic bombardment
• Shell (projectile)
• Projectile point
• Projectile use by animals
• Arrow
• Dart
• Missile
• Sling ammunition
• Spear
• Torpedo
• Range of a projectile
• Space debris
• Trajectory of a projectile

{{Reflist|group=note}}

{{Reflist}}

• {{cite book|author=Heidi Knecht|title=Projectile Technology|url=https://books.google.com/books?id=zS2SBgAAQBAJ&q=Semyonov+chahars|date=29 June 2013|publisher=Springer Science & Business Media|isbn=978-1-4899-1851-2}}

{{Commons category|Projectiles}}

{{Wiktionary}}

• [http://www.phy.ntnu.edu.tw/ntnujava/htmltag.php?code=users.sgeducation.lookang.Projectile02_pkg.Projectile02Applet.class&name=Projectile02&muid=14019 Open Source Physics computer model]
• [http://www.physics-lab.net/applets/projectile-motion Projectile Motion Applet]
• [http://galileo.phys.virginia.edu/classes/109N/more_stuff/Applets/ProjectileMotion/jarapplet.html Another projectile Motion Applet]

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Category:Ammunition

Category:Ballistics