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Alternative Project Assignment

Physics
by

Krista Sherman

on 4 June 2013

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Transcript of Alternative Project Assignment

(Pivot Axle) The Trebuchet The Catapult: Projectile Launching Devices Catapult History of -One of the first recorded uses of the slingshot came about in bible times in the story of David and Goliath.

-While early slingshots were mostly associated with young vandals, they were also capable hunting arms in the hands of a skilled user.

-It was not until the post World War II years saw a surge in the popularity, and legitimacy, of slingshots

-In 1839 Charles Goodyear discovered vulcanization; cooking rubber with sulfer, which created an increase to the rubbers strength and elasticity. The Ballista -The Ballista is believed to be an ancient war engine which was invented by the Greeks (the Scorpion) and modified by the Romans in 400BC.



-Similar to the crossbow, it was tension powered and launched darts. Alternative Project Assignment PHYSICS! Trebuchet Sling Shot Ballista -The catapult has been used since ancient times, and it has been proven to be one of the most effective mechanisms during warfare as well to attack a fortress or a city.


-According to National Geographic News, the exact origin of the catapult is unknown; however, early records suggest that the device may have originated in the Middle East or China.


-A Catapult is any kind of device that shoots or launches a projectile by mechanical means. History of How? -Catapults made their first introduction in England in 1216 during the Siege of Dover; the French crossed the Channel and were the first to use Catapults on English soil. Strength:
-Catapults were used extensively throughout Europe, mostly the French, until 885-886 AD when new defense systems proved catapults ineffective. -The arm of the Catapult is pulled and secured down to be able to load the basket with the object being hurled
-After an object is placed in the basket, the bindings that holds the arm down are released, causing the arm to rapidly move, thus hurling the object at a distance.
-It is believed to range from around 150 to 300 meters, if not more. Where? Weakness: A Catapult's You could fire things such as flaming stones, cattle or even plague victims over the walls of a castle at a safe distance. The catapult wasn't very accurate and as you were preparing the catapult, you could be fired at and you had a better chance of dying. History of The Sling Shot History of -The trebuchet reached Europe during the early Middle Ages, or Dark Ages, in 500 AD and was used extensively by the French. Where? -The trebuchets were well known in medieval times. These were the times of the castles for fortifications.


-These machines were well suited for attacking castles: they could be set up at a safe distance from archers on the castle walls; they could be moved to sections of the walls that had weakened, and they could throw almost anything over the walls and into the areas of the hold.

-A Trebuchet is a gravity powered sling. -The trebuchet is believed to have been created by the Chinese in 300 BC. How? -A trebuchet consists of five basic parts: the frame, counterweight, beam, sling and guide chute.
-The frame supports the other components and provides a raised platform from which to drop the counterweight.
-The counterweight, pulled by gravity alone, rotates the beam. The beam pulls the sling.
-The guide chute guides the sling through the frame and supports the enclosed projectile until acceleration is sufficient to hold it in the sling.
-The sling accelerates and holds the projectile until release. A Trebuchet's Strength: Weakness: With careful aiming and such, they could hit the same spot, or close, pretty consistently. Rate of fire was slow due to the loading time of objects Strength: Weakness: A Slingshot's The slingshot provided accuracy and it was easy to carry. Where? -The earliest types of slingshots were invented in Russia.
-It is certain that slings were known to Neolithic peoples around the Mediterranean, but it seems
likely that the
sling is much older. How? -Person faces away from the target, with their weak hand closest to the target.
-The motion is to move every part of the body in the direction of the target in order to add as much speed as possible to the stone.
-The person releases the projectile near the top of the swing, where the projectile will proceed roughly parallel to the surface of the earth.
-By Newton’s first law, the stone would continue to move in the direction that it was moving just as the force from the sling disappears. Used centripetal acceleration and tangential velocity for projection. Where? -The Ballista was introduced to the Roman Republic in 146 BC by the Greeks.

-The weapon was introduced to England in 1216 during the Siege of Dover - as were many other types of siege engine. -The earliest form of the ballista is thought to have been developed for Dionysius of Syracuse, circa 400 BC. How? A Ballista's Strength: Weakness: - By storing tension in twisted ropes is how ballistas release an object to go far distances.

-When the bow arms of the ballista were pulled back, they twisted the ropes connecting the ends of the two pieces of wood are pulled back creating potential
energy and held in place, while the
bolt, arrow, or dart is put in place.

- It had a massive pull back
action when the bowstring was
released.

-They were used to bombard
walled cities over the walls. The design and building of the Ballista was highly accurate It's range.
It had lighter missiles and could not obtain high momentum THE END! Krista Sherman
Per. 1
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