Projectile

A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance.

[1][2] Although any objects in motion through space are projectiles, they are commonly found in warfare and sports (for example, a thrown baseball, kicked football, fired bullet, shot arrow, stone released from catapult).

[3][4] In ballistics, mathematical equations of motion are used to analyze projectile trajectories through launch, flight, and impact.

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.

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

In military terminology, a rocket is unguided, while a missile is guided.

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.

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).

All kinetic weapons work by attaining a high flight speed — generally supersonic or even up to hypervelocity — and collide with their targets, converting their kinetic energy and relative impulse into destructive shock waves, heat and cavitation.

In kinetic weapons with unpowered flight, the muzzle velocity or launch velocity often determines the effective range and potential damage of the kinetic projectile.

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 (by muscle power, mechanical advantage devices, elastic energy or pneumatics) or chemically (by propellant 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: An object projected at an angle to the horizontal has both the vertical and horizontal components of velocity.

), which is the time taken for the projectile to reach the maximum height from the plane of projection.

= angle made by the projectile with the horizontal axis.

): this is the total time taken for the projectile to fall back to the same plane from which it was projected.

): this is the maximum height attained by the projectile OR the maximum displacement on the vertical axis (y-axis) covered by the projectile.

A projectile being fired from an artillery piece
Projectile and cartridge case for the huge World War II Schwerer Gustav artillery piece. Most projectile weapons use the compression or expansion of gases as their motive force.
Ball speeds of 105 miles per hour (169 km/h) have been recorded in baseball . [ 5 ]
The Homing Overlay Experiment used a metal fan that was rolled up during launch and expanded during flight. The metal has five times as much destructive power as an explosive warhead of the same weight.
Sample from a kinetic energy weapon test. A piece of polycarbonate plastic weighing 7 grams ( 1 ⁄ 4 oz) was fired at an aluminium block at 7 km/s (23,000 ft/s), giving it muzzle energy of 171,500 J (126,500 ft⋅lbf); a typical bullet has muzzle energy of a few thousand joules, with the enormous .950 JDJ reaching 20,000 J (15,000 ft⋅lbf).