1. Lisgar Trebuchet Contest ● Introduction ● History ● Physics ● Rules ● Plan ● Summary

2. Introduction ● Engineering Application of scientific and mathematical principles www.peo.ca ● PEO Engineer In Residence www.eir.ca ● Derrick Oswald DerrickOswald@rogers.com

3. Trebuchet ● Trebuchet, also trebucket (treb-oo-shay') n. A medieval catapult for hurling heavy stones, used during sieges; a heavy war engine for hurling large stones and other missiles. ● It replaced the catapult around the middle of the 13 th century. ● The sling doubles the distance or projectile weight

4. Physics ● It operates by gravity and leverage: the counterpoise or weight and a class 3 lever. ● Variables: - lever distances & height - weight of counterpoise & shot - sling length - pin 'hook' - bearing and slide friction - geometric accuracy - lever mass distribution - release mechanism - sling mass distribution - 'propping' the counterpoise

5. Rules ● Cocked height < 1.5m (meters not miles). ● Mass of counterpoise < 25Kg ● Hurl a standard hardball. ● Score = D / cos Ф D distance Ф trajectory deviation

6. Plan ● Research – 2 weeks, February 28 ● Design – 2 weeks, March 11 (before break) ● Construction/Test – 6 weeks, April 29 ● Contest, May 6 “Sproing Fever”

7. Summary ● Students learn physics and math by designing a trebuchet. ● Students learn about tools, materials, and workmanship by building a trebuchet. ● There's a contest to make it interesting.