Catapult were built and designed by the romans around 400 BC for purposes of war. As more weapons has to be invented, it was used as a siege weapon for damaging higher and stronger walls. There are different versions of catapult, the first catapult was invented around 400 BC in Syracus., it was closely resemble to a crossbow.

The catapult we did in our group is similar with Mangonel Catapult, it's a high accurate siege engine attack weapon, capable of firing higher than 1300 feet, and it was easy to construct, and the wheels that are add made it more Mobilize during war. The catapult has a length of 32 inch, width of 33(1/4) inch, and height of 25(1/8) inch. Made of wood, nails, bungee cords, plastic cup, and a test ball. First the group set up a base with pieces of wood and tightened with nails for support, then created a stopper for the arm, for catching the arm so it would release the ball. Bungee cords are added on the two sides of the stopper,  and the arm was attached by a hinge. The bungee cords and the arm were used to create toque, the bungee cords extend out as being pulled on and the arm retracts it back when its released.

During the test shots for the experiment, we adjusted the shooting angle by adding woods to extend the height. The data we measured for the distances of ball travel is 7.62 meters in 0.99 seconds at an angle of 120 degrees, velocity of the ball is calculate around 7.62m/s and potential energy of the ball is around 0.219 joules.

Many improvement have been done during this lab in our group. We improved the position of bungee to increase the force which can allow the ball goes far away. We applied the third law of force by adding support to increase the opposite force of the arm. We added an extra wood to extend the position of lever arm and we could get a more prefect parabola. We added something soft on the stopper. Because of impulse, by speeding out the force apply by the arm to the stopper less force is applies at one time.

Many improvements could be done to this product if better materials were given,  like heavier wood to make more steady base, a longer lever arm and a bigger angle of the lever arm. However,  a improvement that we could have done is to grab two same size and length bungee cords. By using the same type of cords, as the shot is being released it could create maximum energy and could actually improve the distance and be more effective.

Cite

http://www.midrealm.org/mkyouth/links/catapults.htm

www.medievalchronicles.com/medieval-weapons/castle-siege-weapons/mangonel-siege-weap on/

http://www.medieval-castle-siege-weapons.com/history-of-catapult.html