Can anybody help me understand these terms relating to Handheld Guns used by some law forces?
1. Recoil is the ‘kick’ given by a gun when it is fired. In technical terms, this kick is caused by the gun’s backward momentum, which exactly balances the forward momentum of the projectile, according to Newton’s third law. In most small arms, the momentum is transferred to the ground through the body of the shooter; while in heavier guns such as mounted machine guns or cannons, the momentum is transferred to the ground through a mounting system. The change in momentum results in a force which, according to Newton’s second law, is equal to the time derivative of the backward momentum of the gun. The backward momentum is equal to the mass of the gun multiplied by its reverse velocity. This backward momentum is equal, by the law of conservation of momentum, to the forward momentum of the ejecta of the gun (the projectile(s), wad, sabot, propellant gases, and so on). Provided that the mass and velocity of the ejecta are known, it is possible to calculate its momentum and thus the recoil.
