Okay, first assume a spherical table…
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This is the sort of “physics problem” that is understood by anyone who has experienced gravity.
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As long as the buckets are heavier than the table, everything is fine.
If the table is heavier, the buckets won’t be able to lift it.
Now, imagine the buckets are free to fall below the table: the table goes up.
Physically, it’s no different than a single bucket hanging from a loop: it can go down only as much as the loop will allow.
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Might be handy for when Mr. Creosote pops over for dinner.
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Is it bad that my first reaction was “oh, someone Photoshopped the legs off the table”? I mean, obviously you’ve all explained it above and video shows the installation. But the grainy pic and meme-typography used in this posting screams “viral image NOT REAL”. 
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Not the same, but it reminded me of this:
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This could be a debate to rival tank/nottank…
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The only contact of the complete system (table + buckets) with the environment is through the pulleys at the top. If you consider the forces at those points you see downward forces on both ropes balanced by an upward force on the pulley from the ceiling. The whole system is held up by those forces by the ceiling. What happens within the table/bucket system as you distribute those forces around various parts is irrelevant.
Mike
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The buckets are irrelevant. It’s not a physics problem. It’s just a table hanging from the ceiling.
Remove the buckets and replace them with absolutely anything else that can hold the table’s weight - buckets on the floor, screw the ropes to the table, just tie the ropes off on the pulley - and it’ll hang there just the same. Resting the buckets on the table doesn’t turn it into a crazy confusing situation.
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If your intuition fails you on this, blame your poor intuition - the table is held up by the hooks in the ceiling. How is that not obvious? Did you pass high school Physics?
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Thanks for pointing that out. It actually succeeds as art more than physics puzzle; as physics puzzle it’s too basic to be challenging, but as conceptual art it calls in to question the nature of tableness. That’s the thing that causes some people’s brains to wtf. The physics question is high school freshman, the philosophy question is college freshman.
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Ok, for everyone saying how simple this is - yes, it should be simple, if you’ve taken any physics classes and spent 10 seconds analyzing it. But I think you’re grossly underestimating how much background information you’re bringing to bear that most people, including most students who have taken physics classes, don’t actually have.
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I think you’re grossly underestimating how much background information you’re bringing to bear that most people, including most students who have taken physics classes, don’t actually have.
I think you’re right. A few minutes watching Youtube videos of people playing Kerbal Space Program for the first time show that off nicely. They have no conception of what gravity is or how it should work, no idea what it means to orbit a planet, no idea that staging on a spacecraft is a good thing, or why… Many experienced KSP players are not much better. I’ve seen staggeringly bad explanations of core concepts on the KSP forums. Of course, it doesn’t help that KSP breaks reality in several important ways. Knowledge and subject experience are both forms of privilege and we need to recognize them as such.
It’s simpler to think of a single bucket resting in a stirrup. Hardly needs more explanation than that. This demonstration just baffles you with numbers, but 4 is the same as 1, here. It isn’t fine-tuned - as long as the buckets are heavier than the table nothing can move until the ropes, their anchors, or the table breaks.
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I wonder if Bauhaus did the sound effects?
And the ‘rope’ is actually carefully machined steel rod.
And it’s welded into the faux pullies.
And the entire room has been filled with clear epoxy.
In orbit.
And its a still photograph.
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My goodness, you guys are getting far more complicated than required. The buckets are lag-bolted to the table.
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AnthonyC, no, not really, there are only two pieces of “background information” that are necessary to understand this, and both can easily be obtained with no Physics education whatsoever:
- How pulleys work (as fnc said above)
- The existence of gravity
That’s all. Any first grader who has played with pulleys ought to be able to figure this out. It really is that simple.
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Table is being held up by the hooks in the ceiling mainly. They’re the only reason the ropes are tensioned. Make the ropes longer or shorter and the whole system falls or rises by half of that amount (half the extra string on each side). Make the buckets lighter and the whole system slams into the ceiling. Make them heavier and nothing happens until a string breaks.
It is visually striking but not particularly subtle.
Reminds me of a song I used to hear in Irish pubs, “Why Paddy’s Not at Work Today.” http://www.irishsongs.com/lyrics.php?Action=view&Song_id=386
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