Catapults are a subject that we are all framiliar with here. But these devices have had a profound affect on the history of the worold, as well as human understanding of phyisics. They where developed in ancient times, first used on the battlefield by Alexander the great. The mass of the object being thrown had to be aproximated, as well as the size of the launcher, how gravity would affect the missile, and the distance to the target. This acctually led to the development of some of the first math based phyisics, so that Alexander and his commanders could better hit their targets. These devices enabled Alexander to conquer much of the known world, truimphing over his enemies' superior numbers, city walls, and even elephants. This resulted in a spread of Greek civilization and golden age, as well as spreading learning (includeing phyisics) and one important Greek invention we enjoy very much today: democracy.