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Flying Marshmallows-Catapult Proect

How To Make A Small Mangonel Catapult

Newton's First Law And

Forms Of Energy

Simple Machines

Video on how to make a small mangonel catapult

The Flying Marshmallows

Catapult Project

After the testing day, I decided that the catapult needed more tension to increase the overall distance. To increase the distance the marshmallow traveled, I added 2 vertical 7.5 centimeter pieces of wood behind the vertical pieces and I drilled 2 screws into the 7.5 centimeter vertical pieces on the back so a rubber band could be stretched across the width. Once the rubber band was attached, it gave the arm an extra spring when released. Also, using the dowels as braces, I placed 3 more rubber bands, 2 in front and 1 behind the base of the arm. When the last three rubber bands were attached, the arm of the catapult finally had the strength it needed to fire the marshmallow a sufficient distance.

The Lever

The Mangonel Catapult launched the marshmallow exactly 10.00 meters.

However, Newton's first law, 'every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it', also applies to the catapult. When the arm is released, the rubber bands send the arm flying forward and it would remain in motion if there weren't any objects in its way, restricting movement. The crossbar portrays Newton's first law because it acts as the force stopping the arm, otherwise the arm would forever remain in motion. Newton's second law, F=ma, is represented by the trajectory of the marshmallow. Since the objective was to fire the marshmallow the farthest distance and the marshmallow had such little mass, the force applied to it had to be very powerful.

The simple machines that apply to the overall structure of the catapult are A Lever and A Wedge.

By: Kaia Radeff-Hickman

Period 4

May 21, 2014

The lever contributes to the catapult because the release mechanism is a lever. The applied pressure point is where the elastic is holding down the release mechanism. The fulcrum is the rubber band. And the load is the point on the other side of the rubber band that is being prevented from being lifted by the rubber band.

The Wedge

The Mangonel was originally used in the Middle Ages for firing upon castles with heavy materials. However, modern-day Mangonel catapults are leanched for enjoyment, such as marshmallows.

The wedge contributes to the catapult because it creates a bond between the wood boards. The wedge is a screw, and the screw penetrates either wood board, therefore the spiral rings on the outside of the hold the wood together. In most cases, a wedge is used to split two objects, however in some instances, the wedge machine is used to join the objects.

There were many aspects that went into the overall construction of the catapult. Originally, I used a saw to cut 7 pieces of wood: 2 thirty centimeter pieces and 5 twenty centimeter pieces. With the 30 centimeter pieces and 2 of the 20 centimeter pieces, I used a drill to screw the 20 centimeter pieces 7.5 centimeters vertically into the 30 centimeter pieces, so they are mirror images. They will resemble a T shape. Then, with the 2 thirty centimeter bases, I again screwed them on top of the other 20 centimeter pieces forming a rectangular shaped base.

Newton's Second Law

Newton's Third Law

Newton's second law, F=ma, is represented by the trajectory of the marshmallow. The objective was to fire the marshmallow the farthest distance possible using the constructed catapult. Since the marshmallow had such little mass, the force applied to it had to be very powerful. The rubber bands contributed to the overall spring of the arm which caused the marshmallow to fly. The rubber band halfway up the arm and the rubber band at the base of the arm were very crucial. They both pushed the band back up which exerted the force upon the marshmallow. The final force applied to the arm when I pushed it downwards and the force pushing back up on the arm combined are what influence the trajectory and distance of the marshmallow.

The rubber bands portrayed Newton's third law; 'for every action there is an equal and opposite reaction'. When the rubber bands were extended downward when I pulled the arm down, they were storing the energy needed to propel the arm forward; or in other words, potential energy. According to Newton's law, the force I exerted when pushing the arm downward, was the exact same force that acted upon the arm when the bands pushed the arm back upwards. Also, the kinetic energy was portrayed when the potential energy was released and the arm was in motion. The kinetic energy is what caused the arm to move and the marshmallow to fly.

Once the base was formed, then the final 20 centimeter piece was screwed on the top of the vertical 20 centimeter pieces so that it formed a crossbar for the arm to hit when the arm is eventually released. To form the arm, I took another 35 centimeter piece and drilled a hole in a laundry soap cup and then proceeded to screw the cup to the top of the arm, acting as the basket where the marshmallow sat. On the opposite end of the arm, I drilled another hole all the way through the wood 1 inch from the bottom of the arm. On the rectangular base, I drilled two holes 5 centimeters into the remaining 3 inch sides. I matched the 3 holes and threaded the string through the 3 holes and around 2 plastic dowels acting as placeholders.

Once the string was threaded through all 3 holes and around the dowels, then I started alternating threading the string under and over the arm . The string used was 6 meters long, and once I was out of string to thread, I tied the string off on the dowel to secure it. Once the string was secure, then I took both dowels and twisted them in a forward motion until they would twist no more. Finally, that was what created the tension and caused the catapult to function properly. Since the wood was heavy, the thin string proved to be insufficient. The catapult still fired, however the distance needed to be greatly improved.

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