1. Physics of Catapulting By: Andrea Kuchta

2. Catapults Defensive and offensive weapons that were used in medieval and primeval warfare before artillery was invented Defensive and offensive weapons that were used in medieval and primeval warfare before artillery was invented Forerunner of guns Forerunner of guns Launch projectiles long distances Launch projectiles long distances

3. Items used 1 Ping- pong ball 1 Plastic spoon 1 elastic (rubber band) 1 Paper cup Scotch tape Coins 1 Small (full) plastic bottle 1 small, perfectly round stick of wood

4. Making A Homemade Catapult 1. Put 2 aligned holes in the sides of the cup 1. Be sure they are big enough for the stick (which acts as an axel) to spin freely in 2. Put change in the cup to weigh it down 3. Using tape connect the spoon to the stick 4. Tape the small bottle to the cup between and perpendicular to the holes 5. Tape the elastic to the top of the small bottle 6. Using tape connect the elastic to the spoon so it stays put 7. Place the small piece of wood in the holes

5. The experiment 1. Place the ping-pong ball on the spoon 2. Pull back spoon 3. Record the angle and release 4. Mark the landing point and measure the horizontal distance 5. Repeat steps 1-4 two more times 6. Place data in data table

6. What Happened As I increased the angle of the spoon: As I increased the angle of the spoon: The tension in the elastic increased The tension in the elastic increased Increased the force Increased the force The ping-pong ball gained more potential energy The ping-pong ball gained more potential energy When released: When released: Potential Energy in the ball was converted to Kinetic Energy Potential Energy in the ball was converted to Kinetic Energy The force created by the tension gave the ball even more energy The force created by the tension gave the ball even more energy

7. The Physics Behind It The further you pull the lever back the more tension you are creating in the elastic The further you pull the lever back the more tension you are creating in the elastic As you pull the spoon back you are increasing it’s angle As you pull the spoon back you are increasing it’s angle increases the tension in the elastic increases the tension in the elastic The tension in the elastic creates a force which acts upon the ping-pong ball when it is launched The tension in the elastic creates a force which acts upon the ping-pong ball when it is launched The more tension you create the more energy the ball will be given The more tension you create the more energy the ball will be given Tension and force are equally proportional Tension and force are equally proportional Meaning the greater the tension is the greater force acting on the ping-pong ball will be Meaning the greater the tension is the greater force acting on the ping-pong ball will be The force exerted on the ball gives the ball energy The force exerted on the ball gives the ball energy

8. The Physics Behind It (continued) As you pull the spoon back the ping-pong ball gains potential energy which is converted to kinetic energy when released As you pull the spoon back the ping-pong ball gains potential energy which is converted to kinetic energy when released The angle and horizontal distance are equally proportional The angle and horizontal distance are equally proportional The greater the angle you launch it at the farther it will travel in the horizontal direction The greater the angle you launch it at the farther it will travel in the horizontal direction

9. Bibliography Works Cited Works Cited Dolores Gende: Ap Physics Catapult Project. 7 Feb. 2007. Dolores Gende: Ap Physics Catapult Project. 7 Feb. 2007. Faughn, Jerry S., and Raymond A. Serway. College Physics. 6th ed. Toronto, Ontario, Canada: Thomson, 2003. Faughn, Jerry S., and Raymond A. Serway. College Physics. 6th ed. Toronto, Ontario, Canada: Thomson, 2003. Gurstelle, William. The art of the catapult : build Greek ballistae, Roman onagers, English trebuchets, and more ancient artillery. Chicago, Illinois: Chicago Review, 2004. Gurstelle, William. The art of the catapult : build Greek ballistae, Roman onagers, English trebuchets, and more ancient artillery. Chicago, Illinois: Chicago Review, 2004. “How does a catapult work?” How Stuff Works. 7 Feb. 2007. “How does a catapult work?” How Stuff Works. 7 Feb. 2007. Radlinski, Filip. “Principles of motion.” How Stuff Works. 7 Feb. 2007. Radlinski, Filip. “Principles of motion.” How Stuff Works. 7 Feb. 2007.