View source for Physics:Projectile

{{Short description|Object propelled through the air}}
[[File:155fire.jpg|thumb| A projectile being fired from an [[Engineering:Artillery|artillery]] piece]]
A '''projectile''' is an object that is propelled by the application of an external [[Physics:Force|force]] and then moves freely under the influence of [[Physics:Gravity|gravity]] and air resistance.<ref>{{cite book|last1=Pius|first1=Okeke|last2=Maduka|first2=Anyakoha|title=Senior Secondary School Physics|publisher=Macmillan,Lagos, Nigeria|year=2001}}</ref><ref>{{cite web|url=http://www.merriam-webster.com/dictionary/projectile|title=projectile |website=merriam-webster.com |access-date=13 April 2017}}</ref> Although any objects in [[Physics:Motion|motion]] through space are projectiles, they are commonly found in [[Social:Warfare|warfare]] and sports (for example, a thrown [[Engineering:Baseball (ball)|baseball]], kicked [[Engineering:Ball (association football)|football]], fired [[Engineering:Bullet|bullet]], shot [[Engineering:Arrow|arrow]], stone released from [[Engineering:Catapult|catapult]]).<ref>{{cite web |title=projectile |website=The Free Dictionary |url=http://www.thefreedictionary.com/projectile |access-date=2010-05-19}}</ref><ref>{{cite web |title=projectile |website=Dictionary.com |url=http://dictionary.reference.com/browse/projectile |access-date=2010-05-19}}</ref>

In [[Physics:Ballistics|ballistics]] mathematical [[Physics:Equations of motion|equations of motion]] are used to analyze projectile [[Physics:Trajectory|trajectories]] through launch, [[Physics:Flight|flight]], and [[Physics:Terminal ballistics|impact]].

==Motive force==
[[File:Schwerer Gustav projectile 2.jpg|thumb|right|220px|Projectile and cartridge case for the huge [[Social:World War II|World War II]] ''Schwerer Gustav'' artillery piece.  Most projectile weapons use the compression or expansion of gases as their motive force.]]

[[Engineering:Blowgun|Blowgun]]s and pneumatic rifles use compressed gases, while most other [[Engineering:Gun|gun]]s and [[Engineering:Cannon|cannon]]s utilize expanding gases liberated by sudden chemical reactions by [[Physics:Propellant|propellant]]s like [[Chemistry:Smokeless powder|smokeless powder]]. [[Physics:Light-gas gun|Light-gas gun]]s use a combination of these mechanisms.

[[Engineering:Railgun|Railgun]]s utilize electromagnetic fields to provide a constant acceleration along the entire length of the device, greatly increasing the [[Physics:Muzzle velocity|muzzle velocity]].

Some projectiles provide [[Engineering:Propulsion|propulsion]] during flight by means of a [[Engineering:Rocket engine|rocket engine]] or [[Engineering:Jet engine|jet engine]]. In military terminology, a [[Engineering:Rocket|rocket]] is unguided, while a [[Engineering:Missile|missile]] is [[Engineering:Guided missile|guided]]. Note the two meanings of "rocket" (weapon and engine): an [[Engineering:Intercontinental ballistic missile|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''.

==In sports {{anchor|Sport projectiles}}==
[[Image:baseball.jpg|thumb|Ball speeds of {{convert|105|mph|km/h}} have been recorded in [[baseball]].<ref>{{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}}</ref>
]]
In projectile motion the most important force applied to the ‘projectile’ is the propelling force, in this case the propelling forces are the muscles that act upon the ball to make it move, and the stronger the force applied, the more propelling force, which means the projectile (the ball) will travel farther. See pitching, [[Engineering:Bowling|bowling]].

==As a weapon==

===Delivery projectiles===
Many projectiles, e.g. [[Engineering:Shell (projectile)|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 [[Engineering:Early thermal weapons|early thermal weapons]]), or poisoning (see also [[Chemistry:Arrow poison|arrow poison]]).

===Kinetic projectiles===
{{excerpt|Kinetic energy weapon}}

==Wired projectiles==
Some projectiles stay connected by a cable to the launch equipment after launching it:
* for guidance: [[Engineering:Wire-guided missile|wire-guided missile]] (range up to {{convert|4000|m|disp=or|||}})
* to administer an electric shock, as in the case of a [[Engineering:Taser|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 [[Engineering:Harpoon|harpoon]], or to draw the launcher to the target, as a [[Engineering:Grappling hook|grappling hook]] does.

==Typical projectile speeds==
{{disputed section|date=December 2018}}
<!--the 1m fall is incorrect... it'll be moving 9.8m/s after moving 4.905meters.. not 1-->
<!--i changed the 1m fall  v=g*t with t=sqrt(2s/g) -->
{|class="wikitable"
!rowspan=2 | Projectile
!colspan=4 | [[Physics:Speed|Speed]]
!rowspan=2 | [[Physics:Specific kinetic energy|Specific kinetic energy]] (J/kg)
|-
!(m/s) !! (km/h) !! (ft/s) !! (mph)
|-
|Object falling 1 m (in vacuum, at Earth's surface) || 4.43 || 15.948 || 14.5 || 9.9 ||9.8
|-
|Object falling 10 m (in vacuum, at Earth's surface) || 14 || 50.4 || 46 || 31 ||98
|-
|Thrown [[Engineering:Club (weapon)|club]] (expert thrower) || 40 || 144 || 130 || 90 || 800
|-
|Object falling 100 m (in vacuum, at Earth's surface) || 45 || 162 || 150 || 100 ||980
|-
|Refined (flexible) atlatl dart (expert thrower) || 45 || 162 || 150 || 100 || 1,000
|-
|Ice hockey puck (slapshot, professional player)  || 50 || 180 || 165 || 110 || 1,300
|-
|80-lb-draw pistol [[Engineering:Crossbow|crossbow]] bolt || 58 || 208.8 || 190 || 130 || 1,700
|-
|[[Engineering:Arrow|War arrow]] shot from a 150&nbsp;lbs [[Engineering:English longbow|medieval warbow]] || 63 || 228.2 || 208 || 141 || 2,000
|-
|Blunt Impact Projectile shot from a 40mm [[Engineering:Grenade launcher|grenade launcher]] || 87 || 313.2 || 285 || 194.6 || 3,785
|-
|[[Engineering:Paintball|Paintball]] fired from marker || 91 || 327.6 || 300 || 204 || 4,100
|-
|175-lb-draw [[Engineering:Crossbow|crossbow]] bolt || 97 || 349.2 || 320 || 217 || 4,700
|-
| 6&nbsp;mm Airsoft pellet || 100 || 360 || 328 || 224 || 5,000
|-
|Air Rifle BB 4.5&nbsp;mm || 150 || 540 || 492 || 336 || 11,000
|-
|[[Engineering:Air gun|Air gun]] pellet .177" (magnum-power air rifle) || 305 || 878.4 || 1,000 || 545 || 29,800
|-
|[[Engineering:9×19mm Parabellum|9×19mm]] (bullet of a [[Engineering:Pistol|pistol]]) || 340 || 1224 || 1,116 || 761 || 58,000
|-
|12.7×99 mm (bullet of a heavy [[Engineering:Machine gun|machine gun]]) || 800 || 2,880 || 2,625 || 1,790 || 320,000
|-
|German Tiger I [[Engineering:8.8 cm KwK 36|88 mm]] (tank shell- Pzgr. 39 APCBCHE) || 810 || 2,899 || 2,657 || 1,812 || 328,050
|-
|[[Engineering:5.56×45mm NATO|5.56×45mm]] (standard round used in many modern rifles) || 920 || 3,312 || 3,018 || 2,058 || 470,000
|-
|20×102mm (standard US cannon round used in fighter cannons) || 1,039 || 3,741 || 3,410 || 2,325 || 540,000
|-
|25×140mm ([[Physics:Kinetic energy penetrator|APFSDS]], [[Engineering:Tank|tank]] penetrator) || 1,700 || 6,120 || 5,577 || 3,803 || 1,400,000
|-
|2&nbsp;kg tungsten Slug (from Experimental [[Engineering:Railgun|Railgun]]) || 3,000 || 10,800 || 9,843 || 6,711  || 4,500,000
|-
|[[Engineering:Medium-range ballistic missile|MRBM]] reentry vehicle || Up to 4,000 || Up to 14,000  || Up to 13,000 || Up to 9,000 || Up to 8,000,000
|-
|projectile of a [[Physics:Light-gas gun|light-gas gun]] || Up to 7,000 || Up to 25,000  || Up to 23,000 || Up to 16,000 || Up to 24,000,000
|-
|Satellite in [[Astronomy:Low Earth orbit|low Earth orbit]] || 8,000 || 29,000  || 26,000 || 19,000 || 32,000,000
|-
|[[Engineering:Exoatmospheric Kill Vehicle|Exoatmospheric Kill Vehicle]] || ~10,000 || ~36,000  || ~33,000 || ~22,000 || ~50,000,000
|-
|Projectile (e.g., [[Astronomy:Space debris|space debris]]) and target both in [[Astronomy:Low Earth orbit|low Earth orbit]] || 0–16,000 || ~58,000  || ~53,000 || ~36,000 || ~130,000,000
|-
|7 [[Tera-|T]][[Physics:Electronvolt|eV]] [[Physics:Particle|particle]] in [[Physics:Large Hadron Collider|LHC]]<ref>{{cite web |title=Facts and figures |url=http://public-archive.web.cern.ch/public-archive/en/lhc/Facts-en.html |website=European Organization for Nuclear Research |publisher=[[Organization:CERN|CERN]] |access-date=2018-07-02 |archive-url=https://archive.today/20180702083613/http://public-archive.web.cern.ch/public-archive/en/lhc/Facts-en.html |archive-date=2018-07-02 |date=2008}}</ref> || 299,792,455 <ref group="note">Approximate equivalent of 99,9999991% [[Physics:Speed of light|c]].</ref> || 1,079,252,839 || 983571079 || 670,616,536 || ~6.7 × 10<sup>20</sup> <ref group="note">In relation to the rest mass of [[Physics:Proton|proton]].</ref>
|}

==Equations of motion==
{{main|Physics: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 <math>V_y=U\sin\theta</math> while the horizontal component of the velocity is <math>V_x=U\cos\theta</math>. There are various calculations for projectiles at a specific angle <math>\theta</math>:

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

2. Time of flight (<math>T</math>): 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 <math>T=2U\sin\theta/g</math>.

3. Maximum Height (<math>H</math>): 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 <math>H = U^2 \sin^2\theta/2g</math>.

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

==See also==
* Atlatl
* [[Physics:Ballistics|Ballistics]]
* [[Chemistry:Gunpowder|Gunpowder]]
* [[Engineering:Bullet|Bullet]]
* [[Engineering:Impact depth|Impact depth]]
* [[Physics:Kinetic bombardment|Kinetic bombardment]]
* [[Engineering:Shell (projectile)|Shell (projectile)]]
* [[Engineering:Projectile point|Projectile point]]
* Projectile use by animals
* [[Engineering:Arrow|Arrow]]
* [[Engineering:Dart (missile)|Dart]]
* [[Engineering:Missile|Missile]]
* [[Engineering:Sling (weapon)#Ammunition|Sling ammunition]]
* [[Engineering:Spear|Spear]]
* [[Engineering:Torpedo|Torpedo]]
* [[Physics:Range of a projectile|Range of a projectile]]
* [[Astronomy:Space debris|Space debris]]
* Trajectory of a projectile

==Notes==
{{Reflist|group=note}}

==References==
{{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}}

==External links==
* [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]


[[Category:Projectiles| ]]
[[Category:Ballistics]]

{{Sourceattribution|Projectile}}