Finished Product

Log of Meetings

Date	People Present	Work
4/17/14	Alex, Taylor, Evangeline	Alex researched the dimensions of the catapult for the maximum range. Taylor researched the energy that is present in the launching of the balloon. She took notes. Evangeline researched the force that acts upon the catapult and how Newton’s three laws are present during the launch. Taylor discovered the modifications of energy that needs to change in order to increase the range.
5/12/14	Alex, Taylor, Evangeline	Taylor and Alex drew the diagram showing the forces acting on the catapult. Me and Taylor also searched information for the projectile motion portion.
5/13/14	Taylor	Taylor finished researching the information about projectile motion and added to the post. She also drew a diagram showing projectile motion for the catapult.
5/14/14	Evangeline	Evangeline posted the picture of the force diagram onto the blog.
5/14/14	Alex, Taylor, Evangeline	All three of us met up at Alex’s house and began building the catapult. Evangeline helped cut the wood, and Taylor nailed the wood together. Alex also nailed the wood together and helped hold the wood together while we built it. Alex also helped measure out the wood to build the base.
5/17/14	Alex, Taylor, Evangeline	All three of us met up at Alex’s house to finish and test our catapult. Alex pulled the trigger each trial and measured how many feet the balloon landed. Evangeline helped Alex attach the weights to the catapult. Taylor brought the lacrosse stick over and helped attach it to the arm. All three of us took videos of the trials and explained what changes were made for each launch. Alex and Evangeline filled up water balloons.

Trail Runs

1. First launch

 

 

2.  Second launch: We changed the blue container that holds the balloon to a lacrosse stick. The balloon went about 45 feet this trial.

 

3. Third launch: This time we moved the bar down which increased the length of the arm just to see if the distance would increase. This time the balloon went about 40 feet.

4. Fourth launch: For this run we cut the arm to the right requirement. For this run the balloon didn't go as farther.

 

5. Fifth launch: We added a bar to the base to change the angle and see if it would increase the range.

6. Sixth launch: The last thing we did was add a string to pull the arm back. This time we used a baseball and it went about 35 feet.  

Building our Catapult

Projectile Motion

The variables within projectile motion are the distance of the balloon after being thrown, how long it takes for the balloon to hit the ground, and lastly the maximum height of the balloon when being launched into the air.

A projectile has a horizontal motion component and a vertical motion component. Gravity only affects the vertical motion of a projectile. Because there is nothing affecting the horizontal motion component, the horizontal velocity is constant. Gravity is an acceleration that acts downward. It causes objects moving in an upward direction to slow. On the other hand, it causes objects moving in a downward direction to speed up.

For upwardly launched projectiles the speed that it goes up equals the speed that it hits the ground. The time it takes to reach its highest point equals the time it takes to hit the ground. It's launched with an initial velocity of zero, and to accelerate the projectile a force must be applied. The gravity of the horizontal motion is constant since we assume the acceleration is zero during launching.

The modifications needed to increase the range of the projectile would be to increase the time the balloon is in the air. In order to increase the time that the water balloon is in the air, the speed at which it is launched needs to be faster and the arm of the catapult needs to increase in length. The faster the arm releases the balloon, the faster the balloon will travel therefore increasing the distance within the time it is in the air. The longer the arm is, the farther the balloon will land due to the arm being able to reach a larger height a projecting it further than a shorter catapult arm would.

Force

During the catapult launch Newton's three laws occur. Newton's first law applies as the arm of the catapult swings and launches the balloon. As the arm continues to move back it is stopped by the retaining bar. This explains how an object in motion will stay in motion until an outside force acts upon it. The smaller the mass of the balloon, the more force will be needed to accelerate the balloon. This relates to Newton's second law which states that the acceleration of an object is proportional to the force acting on the object, and is inversely proportional to the mass of the object. As the balloon sits in the arm of the catapult it exerts a force. Then the arm launches the balloon, exerting a force on the balloon. This process uses Newton's third law which states whenever an object exerts a force on another object, the second object exerts an equal/opposite force on the first object.

To increase the Range:
Some modifications that would increase the range would be to add a more heavier weight which would cause the arm to exert more force on the balloon. Also the length of the arm can affect the range. If we were to increase to length of the arm, then the balloon would launch farther and higher. The higher the balloon goes, the longer it will take for gravity to pull it down.  

The Energy Behind a Trebuchet

To put a trebuchet into its "cocked" position, a team of people use their energy to hoist the counterweight. When the counterweight is raised, it gains this energy as potential energy. In this case, the potential energy is gravitational potential energy-energy that results from the position of an object in a gravitational field. The amount of gravitational potential is dependent on both the weight of the object and its position. Since the counterweight in a trebuchet is very heavy, it has a great deal of potential energy. While energy cannot be created or destroyed it can change forms. The potential energy from the raised counterweight is released and begins to fall. The downward motion of the counterweight then causes the sling to swing and the projectile to be released. The potential energy that was stored in the form of kinetic energy, to the projectile, which is released at a high velocity.

To increase the range of the trebuchet, one would have to increase the mass of the object in order to create more potential and kinetic energy within the catapult. After building up more potential and kinetic energy, it will increase the velocity which will, in effect, increase the range of where the projectile will fall.