Trebuchet Arm Ratio Hypothesis

The earliest trebuchets were ‘traction trebuchets’, which were developed in China in the 4th Century B.C.E. Traction trebuchets used human labor instead of a counterweight for power. The Chinese needed so much power for the trebuchet that they had up to 250 soldiers pulling on ropes to operate the machine. This machine could throw stones up to 100 meters, but was not very accurate, because of the inconsistency in using manpower.

Calculations were performed to determine the effectiveness of the design of the platform. Allowing for a safety factor of 1.5 times the design weight of 10kg and considering the bridge must not be overdesigned; plans were made for the bridge to fail at 25kg, 2.5 times that of the design weight. According to the calculations, the bridge would hold a load of over 15kg and experience failure at 20kg in the members. These calculations were later disproven in the testing, breaking 8kg earlier than expected, due to unforseen errors. An analysis of the bridge design and calculations has been included at the end of this report.

Science Buddies. (2015, December 12). Effect of Trebuchet Arm Length or Counterweight Mass on Projectile Distance. Retrieved March 24, 2016, from http://www.sciencebuddies.org/science-fair-projects/project_ideas/ApMech_p013.shtml

To fire it, the spoke or arm was forced down, against the tension of twisted ropes or other springs, by a windlass, and then suddenly released. As the sling swung outwards, one end would release, as with a staff-sling, and the projectile would be hurled forward. The arm would then be caught by a padded beam or bed, when it could be winched back again. The Onager is usually the first type of catapult

A trebuchet is a siege weapon most commonly used in the middle ages. It uses gravity to propel an object. There are competitions held today called "Pumpkin Chunkin '" which use trebuchets to launch pumpkins as far as possible. The common question is what the dimensions should be when making it. Should the arm be longer or shorter? Should the counterweight be heavier or lighter? These questions have been asked by competitors in trebuchet competition as well as engineers. And this is why the project is in the field of mechanical engineering.

Which, really means that we have used physic for a long time. The base on the opposite ends of the cup the fulcrum. When the action of pulling back where the cup you are creating built up potential energy. However, when the cup is release kinetic energy takes over and allows an object (projectile) to fly in order to hit a potential target. (Canavan, 2017) Catapults Building Procedures Gather all materials needed for building each catapult base shape and put them in order.

Compared to the trebuchet, the designs of other siege weapons were lacking in many respects. The most important of these other siege engines included the Greek ballista, the catapult, and variations on the catapult design, such as the Roman onager and mangonel. The ballista's design was very similar to an extremely large crossbow with a guide chute to keep the projectile on path. A large ballista could launch an eight pound stone over 450 yards. It took two men to operate a ballista (Hamper). A standard catapult used the inconsistent strength and weight of men as a source of power. Groups of men had to work to pull down the catapult bar in order to launch the objects. Such catapults could typically throw as much as a fifty pound rock. An onager was type of a catapult with a short arm that would be launched forward by many twisted sinews. Both the onager and the ballista were limited in accuracy and range, because the tightly twisted sinews and ropes continually wore out and needed to be replaced. Likewise, the standard catapult lacked accuracy because of the inconsistent strength and weight of the men who fired it. While all of these siege machines were useful, none of them had the range, or were as powerful, accurate, and widely used as the trebuchet (Gurstelle 18-22).

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the arm on the catapult. My independant variables are the items and their different weights

(Melvin, Mangonel - “Physics of Catapults”) The speed and distance of the projectile depended on how much force the catapult applied to the projectile, and the momentum depended on the mass and the velocity of the projectile (dead diseased cow, or flaming

* The relevance of this experiment is similar to understanding a real airplane. Paper airplane models are derived from an actual plane these days. The design of an airplane has so much to do with distance, hang time, speed, and many other factors. Understanding the models I have chosen to make help me

Purpose: The purpose of this Physics Lab is to investigate what factors determine the amount of flexion of the cantilever. Hence, the objective is to establish a relationship between the length of a cantilever, which may give some insight into the physics of cantilevers.

Case II: The beam was turned around in such way that the shortest side of the cross section is on the support. The steps described in Case I was repeated and data was recorded.

The date was December 17, 2014. I’d been home from school for two days already, due to a bomb threat from a student a few towns over. His timing was convenient for my family, it turned out; we had something to take care of.

Step 9: Because we measured the lengths in centimeters rather than meters, we need to calculate are ‘g’ value into m/s2 so we can compare it to the SI unit for acceleration due to gravity. (Eg. 981.4/100 = 9.81 m/s2)