For comparison, a Roman 1st-century BC catapult using stones of 6.55 kg fired with a kinetic energy of 16,000 joules, while a mid-19th-century 12-pounder gun firing projectiles of 4.1 kg fired the projectile with a kinetic energy of 240,000 joules. Source: Internet
However, the Primitive Archer test used a convert longbow at very short range, generating 160 joules (vs. 73 for Bane and 80 for Williams), so probably not representative of battles of the time. Source: Internet
Lasers have improved dramatically since the 1970s, scaling up in energy and power from a few joules and kilowatts to megajoules (see NIF laser) and hundreds of terawatts, using mostly frequency doubled or tripled light from neodymium glass amplifiers. Source: Internet
High-Energy ICF High energy ICF experiments (multi-hundred joules per shot and greater experiments) began in earnest in the early-1970s, when lasers of the required energy and power were first designed. Source: Internet
It is thus equal to 10 −7 joules or 100 nanojoules ( nJ ) in SI units. Source: Internet
Still, possessing, manufacturing and import/exporting airsoft guns with a muzzle energy not above two joules of kinetic energy is legal to citizens in China's SARs. Source: Internet