Anson+Wong's+Project

Anson Wong's Trebuchet!

Applied Physics Principles:
Potential Energy - This is the energy that is stored within a physical system as a result of its position or configuration. This is applied to trebuchets when you begin to cock/load your trebuchet. By moving the counterweight up into the air, you are adding potential energy to the trebuchet system. The counterweight will fall due to to gravity, and your projectile will fly!

Newton's Law - These are the rules of motion. These apply to all physical objects. A trebuchet is a physical object.

Drag(air resistance) - This is the force That opposes the relative motion of the Christmas ornament. When The Christmas ball is thrown, its motion is opposed by the friction between the air and the ball. The projectile is slowed down, and does not fly as far as it would in a vacuum.

Projectile - A projectile is an object which does not have any force acting upon it, except for gravity and in many cases air resistance. The Ornament is a projectile when launched.

Projectile motion - When The ornament is launched, it follows a trajectory. This trajectory is the shape, or path that the projectile follows while moving. One of the most important things to remember when talking about projectile motion is the concept of forces. When The projectile is launched it will have a vertical force and a horizontal force acting upon it at the same time. The vertical force determines how high the projectile will fly, and the horizontal will depict the range of the throw. In order to achieve the maximum range, the horizontal and vertical forces should be balanced. This give sufficient height, so it can have enough to hang time to travel, while it also gives enough speed for it move horizontally. The angle throw the object to achieve this balance in forces is 45 degrees.

Materials:

 * 1) Wood
 * 2) Screws(around 10, you can always screw things in twice if you want it to be more secure, but make sure the wood does not split.)
 * 3) 1/4" width Washers
 * 4) 1/4" width Nuts
 * 5) A 1/4" width threaded metal rod
 * 6) A large spoon
 * 7) A roll of duct tape.
 * 8) Something that weighs around 600 gram(I used a steel plate)

Tools:

 * 1) A saw(to cut wood and the metal rod)
 * 2) A drill with drill bits
 * 3) Measuring tape
 * 4) A pencil
 * 5) A working area

Base:
1. Cut 4 planks of wood, each with a length of 25 cm long. 2. Screw the four pieces together at each corner so that u get a square. It should looks something like this: 3. Cut out a piece of wood that is not a plank, but has enough width to fit some screws in it. This piece should be 20cm in length. 4. Screw it into the The square you have made. 5. Take a new piece of wood of equal width and place it in between the The secured piece and the plank. This new piece will be the supporting piece. After placing it in, draw with your pencil at what angle you should the wood and at where so it fits perfectly. 6. Screw the new piece on the existing piece and the square base. 7. Drill a hole near the tip of the first piece you secured. It should have a diameter of 0.8cm. This is will be where your threaded rod will be placed. It should look like this: 8. Repeat steps 3-7 on the other side of the square base.

Arm:
1. Cut a piece of wood with a length of 36cm. 2. Drill a 1/4" hole 10cm from the tip and another at 4cm away from that same tip. 3. Cut 2 thin pieces of wood with a length of 8.5 cm. 4.Drill a 1/4" hole 1cm away from the tip on both pieces. 5.Screw on a nut, then feed a thin piece of wood, and then a washer on to a threaded rod.the threaded rod should have a length of 5cm. Cut the rod if you can't find one of this length. 6. Feed the rod through the 36cm piece of wood. It must go through the hole closest to the tip. 7. repeat the step 5 on the other side of the rod. It should look like this:

Completion Phase:
1. Feed A new rod(24cm) through other hole in the arm. 2. Feed washers onto both sides of the the rod. 3. Screw on nuts onto both sides, so that the arm sits in the middle of the rod. 4. Feed the rod with the arm on it through the 2 holes in the base. 5. screw nuts onto both sides. it should look like this: 6. Tape the spoon to the long end of the swinging arm. 7. Tape your heavy object(counterweight) onto the two smaller pieces that are hanging from the swinging arm.

Fire phase:
1. Cut out a piece of wood that is approximately 28cm long. You can vary the length to your preference. This will be used to prop up your counterweight and the length of this piece of wood will depict how high your counterweight will be when it's loaded. 2. Prop this piece of wood under your counterweight. 3. Place the Projectile in the spoon. 4. Kick out the piece of propped piece of wood quickly to send your projectile flying! It should look like this:


 * Trials || Mass(Kg) || Arm Length(m) || Distance(m) || Points(P=D/mL) ||
 * 1 || 1.487 || 0.559 || 3.149 || 3.79 ||
 * 2 || 1.487 || 0.559 || 2.540 || 3.06 ||
 * 3 || 1.487 || 0.559 || 2.690 || 3.24 ||
 * 4 || 1.487 || 0.559 || 2.413 || 2.89 ||
 * 5 || 1.487 || 0.559 || 2.500 || 3.01 ||
 * 6 || 1.487 || 0.559 || 2.286 || 2.77 ||
 * 7 || 1.487 || 0.559 || 3.048 || 3.61 ||
 * 8 || 1.487 || 0.559 || 3.251 || 3.90 ||
 * Average || 1.487 || 0.559 || 2.740 || 3.28 ||

Test procedure:
I Used different arm lengths by moving the spoon. I used a number of different weights and found that Counterweights from 500 grams to 600 grams worked best. I also bent the spoon to see which angle of release worked best. Finally, I Changed how the ornament was placed in the spoon to find the best result. The trial results were all done with what i found to be the best to be the best configuration.

Test Analysis:
I found the two most important factors with this trebuchet design were the angle of release and how the ball was placed in the spoon. To change The angle of release was important because it changed at which angle the ornament flew. I changed the angle by simple bending the spoon. If i wanted it to release later and get a more horizontal angle of release, i would bend the spoon further. If I wanted the angle of release to be more vertical I would bend the spoon more straight or even backwards. The best angle i found was to bend the spoon slightly forwards. The Ornament placement was important because of its shape. The projectile was completely round except for a little stub. This stub was important because it was slightly more heavy than the rest of the ball and would change the trajectory of the entire ornament. The best way to place the ornament was to place it facing towards the tip of the spoon.