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By: Vanessa Schoudt, Lindsey Schaffer, and Noah Kosachuck

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Our catapult closely resembles the design of the mangonel. Each part plays an important role in order to launch the cotton ball. The cardboard is the support to the whole structure in place, and to help trigger the catapult. The popsicle sticks are used as the base of the structure. The clothes pins are used as the post to support the arm and cup. The straw is being used as the rotational device that provides a rotational movement for the catapult to launch. The longer popsicle stick is the arm that connects the cup and straw together. The cup holds the projectile (cotton ball). On the opposite side of the cup (on the popsicle stick) is the rubber band connected to the base. The rubber bands purpose is to provide tension in order to provide power to launch the cotton ball. The rubberband is connected to the arm (popsicle stick) by tape and looped through the base of the structure. At the base of the posts (clothespin) are strips of string that acts an extra support system to the whole structure. They are wrapped around the clothespins and popsicle sticks to form a x. We attached a piece of tape that went from the side of the cup down to the cardboard. We clipped the tape to the edge of the cardboard with a binder clip, which pulled the cup back. When we pulled the binder clip off the cardboard, the catapult would launch.

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The Ballista is one of the different types of ancient catapults. The main purpose of this structure is to launch large stones through the air. This type of catapult looks like a large crossbow. It has two wooden arms that stick out on the sides of the main frame. Connecting these two wooden arms, is a piece of rope. The rope draws back, creating tension, and a projectile gets placed on a beam that the rope rests on. Once the tension has been released by a type of trigger, the rope launches the projectile. This type of catapult was used in military and warfare, and was very portable and easy to carry around (What). A downside of the Ballista is that it was made for small arrows, rocks, and darts, so it didn’t shoot as far as others (Catapults).

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The Mangonel, is closely related to the trebuchet. Instead of mass and gravity as the key part, the mangonel uses torsion or traction as its means for launching projectiles. The main concept to this device was the use of a single arm, connected to a simple structure. The arm is pulled down by the use of a rope twisting around the arm itself until its at the desired position. The structure normally was just a simple box with an A frame, and connected with a horizontal beam. The horizontal beam’s purpose was to stop the arm once the rope was cut. The machine was one of the simpler machines used and was commonly used because it could launch projectiles farther, but at the cost of accuracy (Middle).

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The trebuchet is another well used ancient machine that launches projectiles. This is the oldest of all the catapults. It has a large arm with a sling attached. There are two different types of trebuchets, one is operated by people, whereas the other is operated by a counterweight. They are called the traction and counterpoise trebuchet. The trebuchet was very powerful and able to throw objects very far. A downside to this design is that is is very large, and hard to move around, and it has a complex design (Catapults).

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Find the horizontal component of the projectile’s velocity.

V=d/t

V=2.43sec/2.27m

V=1.07

Divide your average time by two (2).  This is the time it would take to reach its maximum altitude.
1.215 seconds

Use this time to determine the maximum altitude of the projectile.

d=Vi*t+½*a*t^2

d=½*9.98(1.215)^2

d=7.366m

Use the time for maximum altitude to find the initial vertical velocity.

Vf=Vi+at

Vf-Vi=at

Vi=at

Vi=7.366*1.215

Vi=8.950m/sec^2

Use your two velocity components to find your projectile’s initial resultant velocity.

a^2+b^2=c^2

7.366^2+8.95^2=c^2

√7.366+8.95=c

4.039=Initial Resultant velocity

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What Is a Ballista?, users.ece.cmu.edu/~koopman/ballista/defn.html.

How Does a Trebuchet Work?, www.odec.ca/projects/2007/hick7r2/2.html.

MANGONEL,
www.oocities.org/ihusselbee/crusader/mangonel.htm.

“Catapults.” Science Adventures, adventuresofscience.weebly.com/catapults.html.

“Middle Ages for Kids.” Middle Ages, www.lordsandladies.org/.

“Trebuchet.” Wikipedia, Wikimedia Foundation, 30 Oct. 2018, en.wikipedia.org/wiki/Trebuchet.

payment, One-time, et al. “Ballista Medieval Weapon Engraving Vector Image on VectorStock.” VectorStock, www.vectorstock.com/royalty-free-vector/ballista-medieval-weapon-engraving-vector-20730217.

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1. Better trigger. We could have used a horizontal popsicle stick that went across the arm, that we could have flipped to launch the cotton ball.
2. We could have used a thicker rubber band to launch the catapult. We used a very skinny one because we thought it would stretch better, but it didn't give our catapult enough tension to launch very far.
3. We could have used a different object for the rotational movement instead of a straw. The straw was very prone to breakage and wasn't very strong.

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-Cardboard
-String
-Tape
-Popcicle Sticks
-Clothes Pins
-Straw
-Rubber Bands
-Dixie Cup
-Binder Clip
-Cotton Ball