Guns Kelly Wong 10.1 October 28, 2008 Guns Kelly Wong 10.1 October 28, 2008
Guns are a very important invention that has shaped the world. They are also an interesting technological device that exemplifies Newton's third law of motion.
Physics of guns
When a gun is fired, there is a momentum used to propel the bullet forward from the gun. Newton's third law of motion states that "to each and every action, there is an equal and opposite reaction"Ã¯Â¿Â½, so the gun will recoil. The total momentum is therefore equal to zero. The bullet slows down in the air. When the bullet hits the victim, not all of the bullet's energy goes into 'pushing' the victim. Some of it appears as a shock-wave inside their body, while some appears as damage of the bullet or victim.
History of guns
Gunpowder was discovered accidentally when some Chinese alchemists tried
It was first used for military purposes in 919 AD. In the official Song history, 'fire cannons' were made from bamboo filled with gunpowder. The first gun, found in the 1970s in Manchuria, was dated to around 1290 AD. By the 1350s, gunpowder and guns had become common weapons on the battlefield.
Impact on society
Guns are important for self-protection, especially in cities where crime rates are high. In the U.S., guns are used for self-protection against criminals nearly 2 million times per year, 5 times more than guns are used to commit crimes, and 128 times the total number of murders. "According to the National Crime Victimization Surveys, people who use guns to defend themselves are less likely to be attacked or injured than people who use other methods of protection." Ã¯Â¿Â½ On the other hand, people who commit murders...