Trebuchet Challenge Applied Tech Mr Parsons What You

Trebuchet Challenge Applied Tech Mr. Parsons

What You Need to Do l Design and build a trebuchet that can hurl a baseball at least 100 feet l Your assessment will be a Design Brief l There will be a written assignment as well l Outlined in the assignment sheet

Rules of the Road l l l Your project must be safe and unlikely to injure yourself or others. We are limited to 4 equally sized groups per class. If you cannot work the groups out amongst yourselves, I will assign groups. You may use fixed or swinging counterweights. We will be using the rules for the World Pumpkin Chuck Championships…. http: //science. discovery. com/tv/punkinchunkin/contraptions/trebuchet/rules. html You must have a scale drawing of your project before you will be given access to tools or materials.

Rules of the Road Each group will be given five 2 x 4’s. Each 2 x 4 is 8 feet long, giving you 40 linear feet to work with. l The fulcrum of your lever arm can be no longer than 6” long (this subject to change, based upon material availability). l You may use no more than 100 lbs of counterweight. l We will launch each trebuchet 4 times, twice in the first round, twice in the second round. The two distances for each round will be averaged. The higher of the two rounds will be your final average. Between rounds, it is expected that each group will work to improve their design. l

What is the difference between a trebuchet and catapult? l. A catapult uses some sort of elastic material to supply power to the throwing arm l That material could be the arm itself, rope, or any other springy material l. A trebuchet uses a counterweight to supply power l The counterweight could be fixed or rotatable

What is the difference between a trebuchet and catapult? l. A catapult uses a stop of some sort to determine the angle of release l A trebuchet uses a sling to determine the angle of release, meaning that the arm can swing freely

What is the difference between a trebuchet and catapult? stormthecastle. com and inframez. com

Trebuchet Physics l In essence a uses a counterweight on a 1 st class lever to create a force that flings a projectile l l entersection. com picturesof. net

Trebuchet Physics l In this model of how the trebuchet works (http: //www. real-world-physicsproblems. com/trebuchet-physics. html ), the counterweight falls, driving the other side of the arm up quickly, moving the independent sling in a circular motion.

Trebuchets Physics The sling releases, and the projectile is flung. l The arm will continue to move forward after the projectile is released. l

Trebuchet Physics l The hardest part of the operation is determining the angle of release for the projectile, which is controlled by a pin on the end of the swing arm.

Trebuchet Physics l The optimal angle of release is 45 degrees l If the projectile is released too soon, it could fly backwards l If the projectile is released too late, you will lose distance.

Some Variations on a Theme l Your counterweight can either be fixed or free l In other words, the weight can either be attached directly to the counterweight arm or it can be allowed to swing freely from the arm. l Your homework assignment for tonight is to find the advantages and disadvantages of each option.

Some Useful Information l The mass of a my baseball is 142 g l This converts to 5 oz (. 31 lbs), which is useful to know because our counterweights are in lbs. l Our counterweights come in 15 lb increments l I suggest a counterweight to projectile ration of 100: 1 to 150: 1

Some Useful Information l. I strongly suggest that you write your name all over ALL OF YOUR MATERIALS. Lost or wasted materials can be replaced at the cost of points to your project grade. l For 2 x 4’s, this cost will be 1 point/linear foot. In other words, a lost 2 x 4 will cost you 8 points. l Measure twice, cut once!