Girls Bulid a Trebuchet

I am a junior in high school and in my physics class we were told to either bulid a trebuchet or catapolt.
We are a group of girls who were able to bulid a trebuchet that went 29.3 meters. 

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Step 1: Building the Base

In buliding a trebuchet, we start by buliding the base with 2X4's.

We use screws to put them together.

The red 2X4 is 20 inches long.

The blue is 48 inches long.

Step 2: Adding to the Base

 In this step we used two 2X4's to make the height of the base arm (cream color) 48 inches long. (one for each side). We drilled the arms on the inside middle of the base.

We also drilled a hole about 38 inches from the top in the center for our rebarr. (next step) 

Step 3: Throwing Arm

 The rebar and the throwing arm are added in this step.
We used a 2X4 that was 48 inches long.
To make the hole go through on both sides a drill was used. 
Make sure that the rebar or whatever you use goes all the way across and come out on both sides of the base arm.

Step 4: Supporting the Throwing Arm

 The purple is the support for the throwing arm
We made the hole too big; this is to help stabalize it.
We also added plastic ties on both sides of the throwing arm.
The purple is 2X4's about 8 inches long for each side.

Step 5: Wheels

 In this step we added wheels to the bottom.
We found that in research that it is supposed to make the distance further.
Theses are your basic cart wheels form a hard ware store.

Step 6: Bucket

 Bucket was added.
We used a laundary deturgent bucket. 
The bigger you have the bucket the more objects to put in for a further distance.
To make the bucket stay we used a large i-hook that we screwed into the top of the throwing arm. 

Step 7: Pouch

 For this we screwed a nail into the bottom potion of the throwing arm and put electrical tape around it.
Next we got rope that is as long as the throwing arm and folded it in half. Cut in the middle of this .
we made our pouch out of mesh.
Tie the rope on both sides of the mesh.
Now get a key chain ring and tie the rope onto that.

Step 8: How Fast Is It?

 To launch this. you must wrap the end of the rope with out the ring on to the screw with the electrical tape on it. Make sure both sides are equal length. place the ring on the end and pull down on the arm so that that bucket is up top. Use force. Act like Friction. Add as much weight as you thing the bucket can handle. When getting ready to let go, the pouch has to be stretched and in the middle of the base 2X4's. Let go.

This represents Newton's second law: What goes up must come back down.

The speed is almost 300 meters per second.

The velocity is almost 300 meters per second towards the JV softball field.

Step 9: Walking Out!

 When we were walking out to go and launch the rocks created inertia so we couldn't push it any more until we moved them.

For weight we used, large rocks.

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    13 Discussions


    3 years ago

    About how much wood did you use in total?


    8 years ago on Step 9

    I have to make a trebuchet for my physical science class. We had to launch a golf ball 20 yards. I was wondering how far did yours launch? 


    10 years ago on Introduction

    Are you sure about your data and the calculations?

    300ms-1 is almost the speed of sound!

    Your graph's vertical axis is labelled "acceleration" - 300ms-2 is over 30g, roughly ten times that of a Shuttle launch!

    8 replies

    Reply 10 years ago on Introduction

    Look at the amount of noise on the thing, it "goes backwards" at three points, not good data.



    Reply 9 years ago on Introduction

    Someone just reinvigorated this I'ble so I thought I'd take another look.  We can't really tell what is going on from the data; however, your "backwards" comment might not be one of the problems with it.  If the weight is heavy enough and the wheels are aligned and well oiled, a trebuchet will roll backwards once the weight is dropped.  I don't remember where I saw that first (History Channel??) but the mechanics of the thing coupled with gravity work together.  They were able to get more distance when the wheels were allowed to roll freely than when they were locked.  When they replayed the profile video in slow motion, the direction of the weight drop was almost perfectly vertical, because the wheels allowed the whole trebuchet to move.  From appearance it looked like the trebuchet suffered less physical trauma from launching on wheels, too.  Without wheels it creaked and groaned. 


    Reply 10 years ago on Introduction

    If you have no experience with Logger Pro, the program tends to ignore it's own axes and applies a generic label you can change.  The numbers are usually fine (relatively speaking, since the data recorders and output systems are normally suspect), and the output data as well, but I imagine the axes were supposed to be in mm or cm.  It's truly a terrible software package...


    Reply 10 years ago on Introduction

    This is why I want to start a contest to find the world's worst program.  I've heard the label applied to everything from Microsoft Vista to the original punch-card programs.  Personally, I found UCLA's Ion Microprobe control software to be the most inefficient package ever created.
    But in all seriousness, Logger throws out the baby, the bathwater, the tub and the whole house's plumbing to boot.


    Reply 10 years ago on Introduction

    Half the problem with your search is finding people who have used something really bad and used something 10x better so that they realise it...



    Reply 10 years ago on Introduction

    Very true, but at least many users ask about quality on message boards before purchasing software.  It's worked fairly well in the past for me - if you throw out the overly gloating reviews (often corporate plants) and the hate-mail levels (rival plants, or people who don't understand what they bought), the middle ground acts as a good critique.  Level-headed arguments help do the comparison.
    Level-headedness is rare on the Web though...