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Catapults and Propulsion. Milbank High School . What are Catapults?. A machine that stores energy then quickly releases this energy to fire a projectile Usually very large (larger than what a person can carry) Slingshots, bows, etc are “small” catapults. History of Catapults.
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Catapults and Propulsion Milbank High School
What are Catapults? • A machine that stores energy then quickly releases this energy to fire a projectile • Usually very large (larger than what a person can carry) • Slingshots, bows, etc are “small” catapults
History of Catapults • Developed from crossbows • They just got larger and larger • First developed in Greece in 3 or 4th Century B.C. • Most were no longer used after the invention of____________ in the 14th century.
History of Catapults • Projectiles • Stones, arrows, boulders • Dead, infected animals (biological warfare) • Beehives
Types of Catapults • Ballista • Powerful crossbow • Greeks, Romans • Range of over 500 yards
Types of Catapults • Mangonel • Medieval period • Romans • Long distance, bad accuracy
Types of Catapults • Trebuchet • Counterweighted • Could throw 50- 100 kg objects over 300 meters and be fired once every 15 seconds
Types of Catapults • Trebuchet Con’t • Sometimes threw larger stones (1500 kg) to break through walls • Castles were built with lakes around them far enough so the trebuchets couldn’t get close enough to work • http://www.cs.wisc.edu/~englet/catapult.html
Physics of Catapults • http://www.cafepress.com/buy/engineering/-/pv_design_prod/pg_1/p_storeid.76346291/pNo_76346291/id_14677278/opt_/fpt_/c_360/
Physics of Catapults • Some catapults work because of some stored tension • In a rope, bent wood, or possibly rubber bands • Trebuchets • Counterweighing
Physics of Catapults • Ideal launch angle? • 45° • Think of the flight of a baseball home run, or football kickoff