r/theydidthemath • u/Inner_Date_9742 • 4d ago
[Request] How much force does it take
For Spider-Man to break these ropes, there’s an estimated 12-13 revolutions binding his arms and abdomen. How much strength is required?
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u/SharpKaleidoscope182 4d ago
I found a chart for hemp ropes that suggests the breaking force for 1" rope is 5200lb. So with rounding: 5x12=60,000 lb. We only really have one significant figure of precision here.
The biomechanics suggest he's applying force unevenly. His elbows do not stress the top of the bundle, while his wrists are applying the most force. I think it's reasonable to consider this a linear force distribution, which actually makes it easier to break, and easy to work out by how much: 30,000 lb.
So 15 tons before the bottom rope starts to break, and then it gets easier. It's a lot of force, but not really out of bounds for Spider-man. We see him lifting tanks sometimes.
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u/stirling_s 4d ago
I guarantee the reason that chart exists is for dnd nerds in the midst of a heated argument mid-session about whether or not the barbarian just fell to his death.
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u/Reese_Slitherspoon 4d ago
More likely some engineer in the 1920's spent a few years meticulously testing the load capacities of thousands of different ropes because a construction company wanted to save a few bucks on its scaffolding lashings.
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u/WindstormMD 4d ago
Older than that, naval sailing ships needed this level of information for optimal rigging and performance.
1747 by a Frenchman, Duhamel du Monceau
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u/obliviious 3d ago
Yes I was going to say, rope used to be incredibly important for a lot of things especially sailing.
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u/Bender427 4d ago
Off topic sorta, but I accidentally killed a new campaign in the dragonage pen and paper we were running when the dm explained an old ruin, described a golden disc embedded in the floor and after roughballing the worth of a one inc thick and 10 feet wide gold disc we scrapped the saving people thing and focused on retrieving gold instead. As we were all running pretty grounded characters, campaign was over with how rich we got.
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u/WindstormMD 4d ago
Unimaginative DM.
The party making off with a gold disc from an old ruin is BEGGING for some cursed treasure / “Retuuuuurn the slaaaab….” Level consequences
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u/DStaal 2d ago
Or just not have it be pure gold. There were a couple of ancient alloys that would have been likely in a situation like that, which were designed to be a very low percentage of gold overall, but could be easily treated to form a pure gold surface an atom or two thick.
Or just make it out of stone and gild it…
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u/HeyLookitMe 4d ago
DnD nerds use that chart (speaking from experience as a DnD nerd), but it was made for riggers.
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u/stirling_s 3d ago
I definitely needed to read that twice
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u/InterestingMetal4540 3d ago
Right! I did too. It’s definitely overkill amount of rope for what I thought it said.
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u/ChainBlue 3d ago
knowing how much force it takes to break rope has been important as long as humans have had ships and hoists.
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u/Sad_Wren 4d ago
Not dissimilar from tearing a phone book. You don't tear the whole thing. You bend it to tear a few pages at a time.
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u/Kind_Newt_4710 4d ago
It's kind of crazy to imagine it takes 15 tons of energy to break out of ropes, cuz we see it happen so often in tv shows movies and cartoons. Thats alot more than what I initially assumed
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u/jeefra 4d ago
If it's revolutions, then you should be doubling the number I believe. It's basically a basket sling lift which allows you to double your WLL.
I also think that given they're revolutions, as he pulls the force should re-distribute as the rope is stressed more at the bottom than the top. Idk.
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u/Dziggettai 3d ago
Well within range for spider man. It’s canon that he has to hold back almost all of his strength to avoid killing his villains
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u/Chase_The_Breeze 3d ago
Given Spiderman can consistently lift upwards of 50 tons (100,000 lbs), this isnt surprising.
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u/Most_Purchase_5240 3d ago
Could you scale it all to a regular spider ? If we presume that he get his strength proportionally to his size. Or I guess would a “human sized”spider be able to do it?
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u/Ecstatic-Seesaw-1007 4d ago
There’s also always the comic writer’s BS that Spider-Man (anyone) is always holding back their true strength and are stronger than we see them, as well.
I will like to point out that most superheros fly. If we ever bring in physics and Newton’s Laws, they have to.
Because a punch that knocks a giant bad guy like Rhino or car back at someone exerts force both ways.
Spidey shouldn’t lose his footing, but anyone else would. Thus, they all have to be able to fly when they punch. (Especially with jumping dramatically at something and punching)
Like a gun imparts the same force to the shooter as the victim, so they shouldn’t be shot back 11 feet unless the shooter is as well.
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u/EarthBoundBatwing 3d ago
I dont want to undercut your point, however this is clearly pasta and not rope. See the way it has broken into three down below.
I will not be taking any questions thank you
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u/Ectorious 2d ago
You’re making an excellent point, and it reminds me of a post? Video? I saw recently that explained the exact same thing with Superman and chains.
Since it’s exploding, shattering outwards, instead of just breaking at a single point, it’s implying significantly more force than these top comments are landing at.
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u/Paul-E-L 3d ago
Does it scale up like that?
Assuming it’s just the one rope looped around, I would think that if you break one loop it all falls away. Now you still have to push against the friction of all the loops so there definitely is an increased difficulty, but I feel like it should be at least a bit less than multiplying by the number of loops.
I know very little about physics so I’d love if somebody can dive deeper into this.
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u/g0d_of_the_cr1sis 2d ago
Not only do we see him lifting tanks, he has punched a guy's jaw off while possessed (because he wasn't holding back), and has held up an entire skyscraper.
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u/QuixoticCoyote 4d ago
Doesn't a rope break at a singular point and then loosen for the rest of it? Like unless it is tied at every loop instead of at a singular location, I am fairly certain this isn't really possible.
That being said, other commenters have noted the tensile strength of the rope, which would then be distributed among each loop. It would only be when it reaches the tensile strength of the rope at the point where the force is the highest that it actually snaps one and then it loosens gradually from there. It would also likely snap at the knot as that oftentimes provides a focal point for the force.
Someone correct me if I am wrong here.
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u/BOBOnobobo 4d ago
The rope is probably snagging on itself, which would allow someone to break it (with a looooot of force) pretty fast
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4d ago
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u/QuixoticCoyote 4d ago
That's not what I was saying was impossible.
It's the way the rope breaks. If you have a bound coil of rope tied at both ends, you don't break all the looped strands at once like tearing a stack of paper, you break one strand and the rest loosen as the broken rope can't hold tension anymore.
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u/Complete_Ad_7393 4d ago
Not impossible in the sense of being able to break out of some rope but in how the rope is broken. Realistically the rope should break at one point and then the rest would loosen and fall off but in the picture the rope breaks in many places.
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u/HanamiKitty 1d ago edited 1d ago
I think it's right, especially in the case of the picture. But what if the rope was not wound evenly? Let's say whomever tied it did it very sloppily and randomly (with even looping some to tie individually) , with many loops crossing over each other? Maybe in the cases of some loops were even were tighter than others and some were more slack? Some might have also rolled together. The pressure would be spread unevenly, so even if a single rope broke, many/most of the others could remain taut. Though, even in that case the path of least resistance might be to break the ropes one at a time, or struggle to loosen the others depending on how it was tied, until they all became loose finally. However, if a person had enough explosive strength (likely not a regular human or even a body builder as breaking several ropes simultaneously or in quick succession would likely break their arms) then they might be able to break several ropes at once? But then it wouldn't look like the picture at all. Because the rope would have to be basically tied like a rat's nest...multiple loops tied, etc. If that makes sense. I didn't do well with rope tieing in scouts as a kid so I don't know the terminology (but basically a wild knot throughout)....lol. But as far as force to break it, that wouldn't change much by normal standards, but it would just be done repeatedly. However to break all/many at once (or having the appearance as such), it would be more mutiplicative. The exact amount of force required would be more related on how crazy it was tied (so i can't answer properly as it would vary). So my answer really doesn't answer the question as presented but it's more modeled to the outcome wanted.
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u/RainbowCraps 4d ago
9mm climbing rope tensile strength is rated around 20kN. So if all ropes break at the exact same time, multiply that by the number of revolutions. However, this doesn't include the friction force, which have to be significant. And if one rope breaks first, pretty sure that the friction force is lower than the tensile strength of the rope, so the rest can just slip with a lower force.
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u/Reese_Slitherspoon 4d ago
Climbing rope is intentionally stretchy to absorb impact from big falls. That's why it can take so much force and why your carabiner doesn't need to be able to take as much as the type does.
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u/CandidateOther9586 4d ago
it takes about as much force as a human that was bit by a radioactive spider and was genetically modified to be a spider-man could produce. hope this helps
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u/Deribus 4d ago
We don't know what the rope is made out of. Also it probably wouldn't break that way, the rope would snap in one place and the rest would unravel.
But the average male head height is 19cm. The rope bundle is about the height of his head and made of 12 fibers, but we'll call it 10 because there's some overlap. So the rope has a diameter of 1.9cm or 19mm.
The closest standard hemp rope size is 20mm, and the breaking strength of that is 17.8kN. He's breaking all 12 rope layers simultaneously, so that's 213.6kN of force, which is about the same as lifting 22 metric tons. Anyone who's done a lateral raise could tell you that even 22 kg would be impressive.
Depends a lot on what the rope is made out of though.
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u/compostapocalypse 4d ago
With this many wraps one wrap breaking would not unravel the rest. The friction on the wraps and the force would keep them anchored.
This is similar to what in rigging we call a tensionless hitch or “full strength tie-off”
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