PRINCIPLE OF THE CATAPULT
Most of the catapult work with the flat parabolic principle and the lever principle.
First based on the lever principle, give the force on one side of the lever to make sure the stone which is on the another side of the force could gain an intial speed.
Then with the flat parabolic principle, the stone could be thrown out horizontally from the top point of the lever and the potential energy of the stone will be transfered into kinetic energy.
History of the catapult
From the prehistory, people started to make catapult with animals' skins to pelt stones and rocks, which could be more powerful and the distance could be longer. In many centries, catapult played an important role in wars.
ABOUT THE COST
- saws $20
- two meters long wide wood
- two meters long narrow wood
- one and a half meters long round wood
by: Ke Yang Jingbin Yin Chufei Yu Jiayi Zhu
