Projectile

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 a constant acceleration along the entire length of the device, greatly increasing the muzzle velocity.

Some projectiles provide propulsion during flight by means of a rocket engineorjet engine. In military terminology, a rocket is unguided, while a missileisguided. 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.

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, 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).

Kinetic weapons are the oldest and most common ranged weapons used in human history, with the projectiles varying from blunt projectiles such as rocks and round shots, pointed missiles such as arrows, bolts, darts, and javelins, to modern tapered high-velocity impactors such as bullets, flechettes, and penetrators. Typical kinetic weapons accelerate their projectiles mechanically (bymuscle power, mechanical advantage devices, elastic energyorpneumatics) or chemically (bypropellant combustion, as with firearms), but newer technologies are enabling the development of potential weapons using electromagnetically launched projectiles, such as railguns, coilguns and mass drivers. There are also concept weapons that are accelerated by gravity, as in the case of kinetic bombardment weapons designed for space warfare.

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

• for guidance: wire-guided missile (range up to 4,000 metres or 13,000 feet)
• to administer an electric shock, as in the case of a Taser (range up to 10.6 metres or 35 feet); 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.

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 ${\displaystyle V_{y}=U\sin \theta }$  while the horizontal component of the velocity is ${\displaystyle V_{x}=U\cos \theta }$ . There are various calculations for projectiles at a specific angle ${\displaystyle \theta }$ :

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

2. Time of flight (${\displaystyle T}$ ): 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 ${\displaystyle T=2U\sin \theta /g}$ .

3. Maximum Height (${\displaystyle H}$ ): 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 ${\displaystyle H=U^{2}\sin ^{2}\theta /2g}$ .

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

• 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

• Heidi Knecht (29 June 2013). Projectile Technology. Springer Science & Business Media. ISBN 978-1-4899-1851-2.

• Open Source Physics computer model
• Projectile Motion Applet
• Another projectile Motion Applet