1. DESTROY THE CASTLE A Model of a Trebuchet By J. Kalinowski (student) Copyright Microsoft clip art

2. What is a trebuchet? An Medieval war machine A catapult that uses a counterweight for the applied force Copyright www.sca.org.n2/collegium/uni36/medieval_war.html 2002www.sca.org.n2/collegium/uni36/medieval_war.html

3. The Challenge Build a wooden trebuchet that will throw a hackysack at a wooden wall The base of the trebuchet should be able to fit into a square that is 50 centimeters on each side The wall will be placed 3 meters from the trebuchet

4. Predictions Using the equations for projectile motion the projectile should be released at a velocity of 3 meters per second at a height of 0.8 meters The sling arm should be longer than the counterweight arm The hackysack should be released in a horizontal direction EQUATIONS D x = v ix t D y = ½ (9.8 m/s 2 ) t 2 Torque = F (lever arm) Ideal mechanical advantage = effort arm/load arm Actual mechanical advantage = force out/force in

5. The Design The sling arm measured 0.8 meters The sling measured 0.5 meters The counter balance arm measured 0.4 meters The maximum height was 0.75 meters

6. The Diagram 43 cm 75 cm 40 cm 80 cm

7. Actual picture Picture or movie from digital camera

8. Analysis of Trebuchet The sling needed to be extended 10 cm to increase height and speed We found that a counterweight of 1.2 kg gave us the best run The base of the trebuchet should be increased to give more stability

9. Works Cited Burke, Dillion Shiel. “Trebuchet picture”. Posted 2001. Accessed 8 Sept 2002.www.sca.org.n2/collegium/uni36/medieval_war.html Faughn, Jerry and Serway, Raymond, Physics, Holt 2002. Chapter 8 “Rotational Equilibrium and Dynamics”. Geiselman, Kevin A. “Trebuchet Construction Hints and Tips”. Ingenium – Ingenious Machines. Revised 27 May 2002. Accessed 25 August 2002.