Catapulting though Time & Physics
Hurling an object towards one’s enemy may seem as old as time itself. People have hurled fists at each other, thrown spears, and launched giant rocks into enemy territory. The use of catapults, and other objects that hurl projectiles, also seem as old as human civilization itself. The effectiveness of the catapult in flinging objects over a great distance and causing destruction is due to a few basic physics principals that govern force, energy, motion, speed and mass to name a few. The design of the catapult denotes a change in modern warfare to the engineer behind weapons being just as important as the actual soldiers and people who use them.
Projectile-throwing machines are found in three main categories: the catapult, the ballista, and the trebuchet (How Stuff Works). The catapult has a lever arm attached to a “bucket” that is usually pulled back by rope and the projectile is released when the rope is cut (How Stuff Works). The ballista is basically a giant crossbow and the trebuchet is similar to the catapult but is a weighted beam with a sling carrying the projectile (How Stuff Works). In this examination, we will mainly be discussing the design of the catapult and trebuchet.
Catapults have been traced back to many different civilizations throughout history, but its modern origins are usually attributed to the Greeks and the ancient scientist Archimedes who designed them (Paul 58). We know that in 339 A.D. Dionysius ordered their design in Syracus (Hansen), but their history goes back even further. The first recorded description of the catapult found in the Bible 2,800 years ago (Paul 58). One passage gives the following description of a ruler of the kingdom of Judah :
And in Jerusalem, he made engines of war invented, to be on the towers and on the corners, for the purpose of shooting arrows and great stones.” (Paul 58).
We can look at the catapult as a lever which is meant to change direction and/or multiply the force that is applied to the projectile. A lever has three locations: the fulcrum, on which the lever arm rotates; the load, where the mass is located on the lever arm; and the effort, where the force, a push or pull, is applied (Vogel 178). It is meant to throw an object a certain horizontal distance in a certain, short time frame so that its impact would be greater than just a human hurling a giant rock at a building. We might intrinsically know this. “Probably no mechanical device is older than the lever; simple and versatile, it’s no doubt older than we humans,” mentions Steve Vogel in Cat’s Paws and Catapults (Vogel 178). If a larger kid jumps from a tree onto a seesaw with a smaller child will be launched into the air. The physics principals that govern the catapult also govern force, mass, speed and acceleration, rotational motion, and projectile motion. From these principals we find out what the optimum projectile mass, lever arm length, time, and launch angle which...