During our physics class, while we were learning acceleration,speed,force, and etc.. We decided to build a catapult since the arm puts acceleration,speed, and force into the invention. So our class decided to test how far we can launch the golf balls by building a mini- catapult (because of the small doors) also we could design it anyway we wanted. But first we needed to know what we were going to bring, so for ours we had at least 4 large 2X4's, a can for the "hand", a metal pipe for the arm, 2 large springs, and a steel pipe for latching the springs with the pipe. Also we tested our catapults acceleration and it came up to 125 m/s squared. Which the according to Newton's Second Law the golf ball's distance should've went about 76 but our final was 22.8m which was less then we expected out of our catapult. So this is how we built it:
Step 1: How to Start It
To build the catapult we had to build it by using 2 out of the 3 large 2X4's, cutting both into 2 90inches and 140 inchs. both 140 inch boards are the length and the 90's as width. After cutting them, we screwed them together with metal brackets in each corner just to make sure they wouldn't move.
Step 2: Slowly But Surely Getting Their
The next step we did was to cut the 3rd large 2X4 into 2 one and a half foot boards. These boards are to attach to the inside so we can put the 2 pipes in.After attaching them vertically to the inside of the base, we drilled them down to the base with 2 more metal brackets. Also we had to drill holes starting from the top we went 10inchs down and drilled a hole then the 2nd hole was at 37 inchs.
Step 3: Getting It Finally Done..
After we drilled in the holes, we had to drill 2 holes into the pole so we can attach springs and insert the rebar in. The hole for the springs had to be under and smaller then the hole for the rebar. So after we drilled in the holes for the rebar and the springs we attached 1 end of the springs to the pipe while the other end went and attached to the steel pole. Another thing is that we needed to find a "stop" for the arm of the catapult so we decided to drill a 2X4 the same size as the ones we used for the width, to use as a stop for the arm. (To see example go back to the intro)
Step 4: Final Step
After drilling in the 2x4 on the catapult and setting everything up the only thing you need to do is to get a golf ball and launch it. But the distance should go up to 76m because of Newton's Second Law but for the final testing it only went 22.8m, which was a huge disappointment.