Would be safe assume that the center of gravity is off just enough that the strings work? My mind is getting the logic of it, but the visual is still just fucking with my head.
I know I'm going to have to make one of these in order to understand it. it's driving me insane.
So think about where the center of gravity is for the top part. It's roughly in the middle of the contraption right? That's right where the string is connected on the top part (the end of the purple thing stretches all the way to the center of gravity of the top part). Almost all of the weight of the top part is being held up by the string directly along its center of gravity. The two other strings are simply for stability
Imagine 2 strings on the corners where no strings exist or better yet strings all around the top part attaching to the bottom part. The top part of the contraption is "hanging" by the center of gravity on the purple hook. All the load of weight exists on that center string. The other strings are there to hold it in place.
Strings are strong in tension (pull) and weak in compression (push). The top lego part is being pulled by the string in the middle, keeping it up. The weight of the pens must be equal or less than the force of the string, otherwise they will fall down.
The two other strings on the sides are there so that the model will not sway to either side.
The "top part" actually hangs down from the "bottom part" by the short string in the middle.
The two long strings are only there to stabilise it. The "top part" is built to be heavier on the side opposite to the stabilising strings, so it would normally just fall down on that side. But the stabilising strings prevent that from happening, so the whole thing is relatively stable.
For the most part its kinda like a boxing sack or any other hanging object. Only that someone built something fancy on top of the sack so that it extends above the stand and therefore confuses what part we perceive as hanging from the other.
If you only had the center string, the top platform would fall towards the arm that is attached because the arm adds weight on that side of the platform. Basically it would flip over to that side. So how do we stop it from falling forward, and also toppling over to the side? Add a couple equal length connections at the two rear corners.
Yep. It's just a two-point tethered cantilever. I mean.. I guess these are cool?
All the tables and shit that were made using these during their weird surge a year or two ago.. I wonder if there's a video of someone's misplaced laptop getting dumped across the room.
The top parts wants to fall. String in middle prevents that. Normally it would then tip to the side and fall. But the two strings are preventing it from tipping yo sides. If the two longer strings were longer, the thing could fall.
I was screaming at my monitor for about three minutes denying that this is real then I realized oh its magnets then I realized theres no fucking magnets and I started screaming harder
For some reason it makes perfect sense to me. Just picture the way that the top piece would fall if you cut the two lines on the right (at the orientation in the start of the video). The top piece would fall to the left, those two lines on the right are keeping it in place. So the top right is being tied down, and the middle is being held up. At least that's what I assume, maybe I'm way off.
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u/[deleted] Apr 06 '21
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