From ancient Greece to modern times

To activate the machine it was necessary to lower the bloom horizzontally and put the bullet in the spoon that was shot with the click. The bloom came back and the bullet described a parabola. The catapul was a machine for siege that was built with wood and it was formed by a base, two vertical uprights, a crosspiece, a “spoon” that pulled very heavy objects.

The first catapult in history was the «ballista» that appeared in the Greek world and for the first time was used by Dionosio of Syracuse and Onomarco to attack the Carthaginian fleet that arrived to help Mozia, that Dionosio wanted to win.

Types of catapult

* Voltage catapult

* Gravitational catapult

* Tensile catapult

The onagro was a war machine aimed at the launch of solid masses. It was designed by the Romans, but was also used by other people such as Byzantines in the Middle Ages. It is known in English as "mangonel", but it has nothing to do with the real mangle, that was a medieval throwing machine moved by many men with ropes.Its name probably derives from the eponymous wild ass of Asian origin whose kicking was compared to the characteristics of the weapon. In fact, when the pole hit the stop the force of the blow raised the back of the onagro, like a a donkey kicking with the hind legs.

* When releasing the arm the ropes tend to return to their original position of rest, thus providing the driving force for the launch of the load. The energy released depends on the material of the fibers used, the number of beams and the extent of the twist applied on them. The launch of a projectile with the catapult follows the laws of ballistics, i.e. that branch of the physical mechanics studying the motion of a bullet as inert body subjected to gravity and to viscous friction of the air. The object launched from the catapult has an initial velocity impressed upon by a force of impulsive type, but its propulsion proceeds by inertia and when the speed has been consumed, it falls to the ground.

* Pillar= where the pole bumps when unhooked. * Pole= it ends with a spoon which contains the projectile. * Hook= it holds the pole. * Basis= where the catapult is placed. * Holes= to insert the rope.

I.I.S.S. «O.Del Prete» Sava (TA) Classe 2^ A Meccanica Anno scolastico 2014/2015