Physics Project: Launch water balloons at your teachers with catapults
20 replies, posted
So a day in the life of AP Physics our teacher announced our catapult project.
[img]http://www.dugnorth.com/blog/uploaded_images/Floating-Arm-Trebuchet.jpg[/img]
My partners decided that we are going to make a [b]Floating-Arm Trebuchet[/b] as opposed to the more simple variants.
I am wondering if there are any [b]good bill of materials[/b] out there that Facepunch may recommend. We are already starting up on schematics and wondering where to get the weights. Our teachers requirements are the following:
[b]It must have a minimum range of 3 meters
It must reach as over a basketball hoop[/b]
Extra credit goes for consistent precision and accuracy and farther range, and I really want to hit my chemistry teacher.
I am also wondering if there any aiming devices that would be used for catapults other than trial-and-error. Any devices that can calculate ranges by inputting amount of weight of the projectiles, and the counterweights?
And how should the catapult be held together? I was thinking of using a bunch of metal corner braces and a screwing them in just to fasten them. I really don't want this thing to smack me in the face on our first test trial.
[QUOTE=CabooseRvB;25519435]more simpler[/QUOTE]
good thing you're in AP physics because you would fail AP English
Super
[QUOTE=ButtsexV3;25519462]good thing you're in AP physics because you would fail AP English[/QUOTE]
It makes the thread funner.
Switch in a grenade at the last second.
no more school forever
This shouldn't be too hard man.
In sixth grade we had a medieval fair at my school, and a friend and I built a foot-tall trebuchet out of sticks we found lying around our back yards, a coat hangar (axis), some leather strap and some screws, and it shot heavy marbles as far and high as your targets.
It was this type;
[img_thumb]http://www.edupic.net/Images/SimpleMachines/trebuchet.gif[/img_thumb]
Not as reliable as some other models but it was pretty accurate when it worked.
Basically, if you have guidelines you'll be fine.
Use 2x4's, pine will do. It's cheaper than most other materials and should handle quite a lot of force, just make sure you support it properly. Wood screws to hold together, etc. For a mangonel type of catapult, there would be a lot of force on whatever is stopping the arm. You don't have that problem, so pine and wood screws will do just fine.
Remember, measure twice, cut once. Same goes for pilot holes. :p
Additionally, if you have access to some solid modelling software at your school, Autodesk Inventor or what have you, model your machine. Often times I've been able to spot easy to solve but previously unknown huge flaws in my designs by modelling them first.
I've read your previous thread where you tell us the amazing story of you starting an AP science class as well as this one and they both give me a annoyed impression that you're just trying to find a way somehow to tell us that you're taking "AP" classes (which doesn't mean anything). I take full IB classes, yet I don't make threads on every random assignments, mostly because people couldn't care less.
If you want help, read whichever physics book you were assigned or look up these things online, you will find much better suited answers than on Facepunch.
Sorry for the rant, I'm just tired of seeing threads like these plaguing the GD.
[QUOTE=Plastical;25519850]I've read your previous thread where you tell us the amazing story of you starting an AP science class as well as this one and they both give me a annoyed impression that you're just trying to find a way somehow to tell us that you're taking "AP" classes (which doesn't mean anything). I take full IB classes, yet I don't make threads on every random assignments, mostly because people couldn't care less.
If you want help, read whichever physics book you were assigned or look up these things online, you will find much better suited answers than on Facepunch.
Sorry for the rant, I'm just tired of seeing threads like these plaguing the GD.[/QUOTE]
I find blogs and FT in GD.
What's AP classes anyway?
If you have steel/aluminum and have the skills to weld it then, in my opinion be easier. I made a more "simple variant" of a trebuchet just last week for my physics class.
I used steel for the base and the arms, and I use aluminum for the arm since it is a lot lighter. I could send you my .dwf files as a .pdf if you wanted.
[QUOTE=johnT447;25520095]What's AP classes anyway?[/QUOTE]
Advanced Placement.
My physics class is cooler, we built a scale roller coaster. That had motherfucking freefall.
I did this too
in 6th grade
[QUOTE=QuikKill;25520135]If you have steel/aluminum and have the skills to weld it then, in my opinion be easier. I made a more "simple variant" of a trebuchet just last week for my physics class.
I used steel for the base and the arms, and I use aluminum for the arm since it is a lot lighter. I could send you my .dwf files as a .pdf if you wanted.[/QUOTE]
We're planning on getting most of our materials out of Home Depot. Wouldn't the metal be a little more pricey?
I built a mangonel once out of scrap wood and bungee cords. I was an overly obsessive fan of RTSs when I was younger. It actually flung shit a nice distance too.
[QUOTE=CabooseRvB;25520217]We're planning on getting most of our materials out of Home Depot. Wouldn't the metal be a little more pricey?[/QUOTE]
It could be, but I live in a line of machinists and engineers and I got it all for free. You would need a lot less steel than you would with wood.
Use the equations you know to find an approximation of where the balloon will land. Make sure to take into account components of the vector when the ball is released, make test runs to figure out the vector magnitude and direction.
Use this: V^2=V0^2 + 2aΔx [i]or[/i] Δx = V0 + 1/2aT^2
You know what I mean, hopefully.
[QUOTE=Comcastic;25520216]I did this too
in 6th grade[/QUOTE]
You're cool.
[QUOTE=Badunkadunk;25520269]You're cool.[/QUOTE]
Just don't acknowledge the useless comments and maybe they'll go away.
For a minimum of 3 meters you will not have to use anything stronger than pine 2x4s a mentioned above. Just use regular wood screws and glue to hold it together. When I made mine I didn't even use screws, just glue, and the arm was 1.5 feet or about 45cm. I used lead for weights. I don't know where you can get it but I would assume any Home Depot or the similar would carry rolls of it for roof flashing. For the release mechanism I put a nail in the end of the arm and bent it a bit. I drilled a hole through a wooden ball and put a string through. I used trial and error to determine the right length of string.
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