Catapult

The Ratapult

Objective:

My objective in this project was to produce a rat-trap powered catapult. It has a base of 30 cm by 30 cm, and has a theme of cows trying to escape the farm. The reason they want to escape is because they are being killed and turned into steaks, against there will. That is why I developed this ratapult, to save the cows. The cows also wanted me to ask you to eat more chicken.

Hypothesis and Drawing:

I hypothesize that if I build the ratapult to a 25-degree angle, and release the hacky sack at a height of .55m then there will be enough velocity to project the hacky sack exactly four meters. The ratapult will release the hacky sack with an initial velocity of 5.8 m/s, and as a result the hacky sack will travel 4.0 meters in .75 seconds.

Procedure:

The first step I took was to paint all of the wood white. After that I put wallpaper on the board that I am going to nail the rat trap to. I then attached the measuring cup to the rat trap by drilling a hole in the middle of the measuring cup and then using string to attach the cup at both the drilled hole, and the hole at the bottom. Then I nailed the rat trap into the board with wallpaper. That board was then nailed into the base.

Then I attached the "steps" to the milk crate. The steps will hold the base of the ratapult at a 25-degree angle. I attached the "steps" by drilling holes in the bottom of them and then tying them to the milk crate. Then I nailed the board with wallpaper into the back end of the base. The base was then nailed into the "steps", and glued grass decorations and cardboard cows to the base. The ratapult was completed.

Data & Observations:

I found the initial velocity, or Vi, by finding the horizontal velocity, or Vx, and then using the equation Vx = Vi * cos(angle).

The angle was 25 degrees, so I input that into the equation also. That made the equation look like

5.3 m/s = Vi * cos(25)

I