The last step we took in completing our Trebuchet was painting and making it look presentable.

History of a Trebuchet Catapult

• ·         The word ‘Trebuchet” is derived from the Old English word ‘Trebucher’ meaning to throw over.
• ·         It was believed to be invented in China in 300BC but more commonly known in England.
• ·         The Trebuchet catapult was first introduced to England in 1216
• ·         The first Trebuchet was powered by men but was later improved [during the Middle Ages] to rely on a huge counterweight that swung a long arm.

Parts of a Trebuchet Catapult

·         A trebuchet consists of five basic parts: the frame(base), counterweight, beam(arm), sling and release mechanism. 

Physics

The trebuchet works by taking the energy of a falling counterweight to throw a projectile. many forces act on the catapult such as gravity and tension. For example gravity is what caused the counterweight to fall and there is friction between the axles and the arm, there is friction between the table and the base, and there is friction between the projectile and the sling. And there is forces on all the forces; according to Newton's third law of motion, whenever one objects exerts a force on one object, the second object exerts an equal and opposite force on the first object.
Newton's second law F=ma  explains trebuchets because the acceleration of the trebuchet is created by the mass of the weight. The net force is created by the weight pulling the arm, which causes the arm so fling up, bringing the sling with it.

Range (max) = 2 * (m1/m2) * h equation used to calculate distance of the projectile.



How it Works..
Once the trebuchet is locked in place, there is potential energy and once the it is released the counterweight drops and it turns to kinetic energy. Then as the weight continues to drop the arm is shot up very quickly. Centrifugal force keeps the projectile in the sling. AS, the sling continues forces try to straighten the sling causing it to unhook and sending the projectile to continue on its way.
 

Now it was time for the trials!

This was one of our first trials with our first sling design. The ball actually rolled backwards. The sling we used didn't cup very well.

This was our next trial. We improved our sling and also added a 15 pound weight. The uneven ground affected its preformance compared to the smooth surface on the patio, but at least it went forward this time.

This wasn't exactly our last trial, but we went back and adjusted the nail at the top which had a big impact on on the arch and distance. Plus we went with a more sturdy material for the sling to keep the distance consistent.

Both examples of some successful and not so successful trial runs.

Finally we finished the base of our catapult! The electric screwdriver is now one of our favorite tools!

Then a miracle happened and Jada's dad got home and taught us how to use the electric screwdriver! We were able to save much more time!

 Our simple release mechanism. all it took was some sting, a screw and some pliers

Attached our weight with notches we cut in the wood and tying the rope very very tightly.

with our catapult build we were ready to start the trials.

Third meeting!

We are starting to build our project's base! We had no help therefore it took us a few hours to hand screw in the screws...since we were both unable to use the electric screwdriver.