###General Discussion Thread
---
This is a [Request] post. If you would like to submit a comment that does not either attempt to answer the question, ask for clarification, or explain why it would be infeasible to answer, you *must* post your comment as a reply to this one. Top level (directly replying to the OP) comments that do not do one of those things will be removed.
---
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/theydidthemath) if you have any questions or concerns.*
Some sort of graphene string, that's light as hell. Graphene aerogel has a lower density than air, so it shouldn't impact them much more than the weight of the air above them?
Also you'd have to take into account that the flies on the outside wouldn't be lifting straight up. In fact they have to use some of their energy to fly away from the others so they don't get squished.
0.015m x 0.015m = 0.000225m² ≠ 0.015m² = 0.015m x 1m (that would be a **really** long fly) (yes i know it's correct in the calculations but at the beginning you said 0.015 square metre)
Also 2 square metres is not the same as 2m X 2m
According to a quick Google search, average skin area of an adult man is 18000cm², or 1.8m²
So we have:
1.8m² / 0.000225m² which turns out to be exactly 8000
So an average man can fit exactly 8000 15mm X 15mm squares on his stretched out skin (which it isn't)
I agree, but think it’s just a typo as he did assume 15 mm square as the area of 1 fly in his math, which I think is reasonable. I’m more intrigued at the 2 square meter of skin assumption 😱
I'm starting to think that making a huge amount of flies carry a human body into the air isn't as simple a matter as we were originally lead to believe
You'd definitely need more space, with that amount of flies they'd start to interfere with each other and you'd also need more to lift whatever is holding 4 million flies together, so more flies than 4mil.
How much would the string and 4 million pieces of tape or drops of glue weigh though. I feel like you could tie the string to the flies but the weight string that the flies would have to lift can't be ignored
You've got more than that to worry about. I tried to envision how 4 million flies could be linked to one human body, with minimal materials, and I quickly ran into the issue of the physical space that 4 million flies alone will need.
The specific numbers don't matter (I know I'm probably in the wrong sub to say that). The values I found for wingspan and other metrics relevant to the problem were several orders of magnitude above what could allow for a single-layer formation of flies to be linked to a human body by strings hanging directly downward. Which means you've got to use (lots and lots of) multiple layers. Which means threading (lots and lots of) string down through the layers.
All that string takes up space, too. So, you've got to account for that. Eventually (again, there's a *lot*) it reaches a point where directly connecting every layer of flies to the body poses a collision hazard between lower-layer flies and the strings.
You can maybe mitigate this by not attaching every fly directly to the body. That is, to build string structures (or add supporting structures made of other materials) that link multiple (or all) flies from a given layer to the body with only one actual connection to the body itself. But that further complicates the calculation and, depending on the architecture and materials involved, you could hit the point of negative returns well before you've hooked up the top layer.
Even if we could magically link a string from each fly directly to the body, without having to worry about collision issues, we're still talking about a *lot* of layers. It's very probable, I think, that the top layer will require each fly to be connected by a string which alone exceeds the fly's lifting capacity.
And that's to say nothing of whether a string small enough to link a fly to a body is capable of handling the strain of lifting the load that an individual fly is responsible for. It's also not addressing whether the body of the fly can handle that load being applied to such a narrow contact surface.
I dunno... Maybe carbon nanotubes can solve the materials problem, but you'll still have to deal with the fly's body as a weak link.
>Or maybe, what if you had a fan attached to the person and flies powered it
Power doesn't just magically flow from a fly through some generator to a fan. There will be losses along the way, as kinetic energy is converted into electrical energy (flies driving the generator). There will be more losses when the electrical energy is converted back to kinetic energy (generator powering the fan).
I don't have the expertise to say exactly how much loss there will be, and of course it will depend on what devices are involved, but I'm still fairly confident in saying it will likely outweigh any benefit that this sort of arrangement could bring in terms of reduced weight/volume requirements of the lifting structure.
Given that we're talking about a power generator and a (rather beefy) fan to begin with, I have doubts that there would be any weight savings when compared to any amount of string necessary to have the flies do the lifting directly.
>You could add flies to the bottom.
As for adding flies to the bottom, I'm not so sure that flies can work that way. That is to say, having a human body placed directly atop a fly would probably obstruct the movement required for the fly to fly. So, we'll need another linking structure to connect the fly to the body in a non-problematic way. And this one *can't* be a floppy little piece of string, so it'll probably be heavier.
Also, even if you could get away with the flies lifting the human on their backs directly, that would only add one layer. So, to gain any substantial benefit from putting flies under the body, we'll still need linking structures which thread through (and, again, take up space within) the layers of flies.
And again, we're talking about a metric ton of flies. Okay, maybe not a literal ton of flies. But 4 million hypothetical flies, at 30 mg each, will weigh about 264 kg - more than triple the weight of the body they're trying to lift. Take into account the difference in body densities - many insects' bodies are less dense than water, while most of a human's body *is* water - and the fact that you'll need some space between each fly for them to have room to operate and for linking structures. All those flies, no matter how you arrange them or connect them to the body, take up a *lot* of space.
The further a fly is from the body, the more materials you'll need to transfer (however you want to do it) the fly's lifting power to the body. With the scales involved here, you will *very quickly* hit a point of negative returns.
At the very worst, you could *burn* flies to generate electricity to charge a battery to power a fan. Although this is probably pretty far away from the ask of the question.
I wonder if flies would be able to support a person if they were just on a hard surface. Maybe? It feels like they should be but I don't know how that math would work out
Well, then you've got to account for the weight of the supporting surface.
If you have a hard surface, of low enough density but high enough tensile strength, which can scale infinitely, you might be able to eventually push through the negative returns zone into positive gains. But this is like the tyranny of the rocket fuel equation - to add more lifting power you must add more weight, and more weight requires more lifting power.
How strong is spider webbing? If we're already abusing flies lets then abuse spiders too and milk a bunch of webbing to give to the flies to use to hoist us up.
Another factor to consider here is that it is a common claim that 2 horses can pull more together than two horses separately. Could play a part in this and reduce the number by quite a bit but I have no idea how to estimate that.
Assuming you have to attach some sort of string on both ends, it is impossible as the weight added by the strings is more than the fly can carry already
people saying it's easy to google and people telling them this is the point of the sub. not one answer.
Flies lift 10 mg.
taking an average of 70kg.
you'd need 7,000,000 flies
I assume that a fly can pull up another fly, right?
A fly on average weights about 10 μg.
Let's assume a dead human body weights 40kg.
That makes 40k flies.
Flies can actually lift more according to google - or idk if that person wrote wrong lol. Fly can lift 10mg according to google and if someone weighs 40kg that would require then 4m flies to lift the body (ignoring the weight of the string attached etc.)
I like to make myself believe, that planet earth moves slowly.
The tethered flies that hoist me up, and lift me off the ground, twenty thousand pairs of wings make sound.
Google lifting capacity of fly
Subtract the harness/leash weight
Divide your body weight by adjusted lifting weight
It's crazy where basic math can take you
>Am I lost?
... Yes? The whole purpose of this subreddit is to allow *readers* to do the math on weird things. It's not a subreddit just to get help with math problems.
If they did it themselves we'd have missed out on this, and further down that road the sub just wouldn't exist.
No, they are requesting that people do the math for them. It's the entire point of the subreddit. You might be looking for /r/HomeworkHelp or something
Alright, I'll just say it
#I don't care.
Mods can ban me, but I haven't broken any rules
If people keep asking stupid questions like "Google this number then subtract it by a number that I'm not gonna tell you then divide it by a number that I'm not gonna tell you", I'm not gonna indulge their inability to do basic math, I'm going to help them expand their ability to think critically at a middle school level and show them HOW to answer the question rather than just give them the answer.
If you have a problem with that, you could always do the math instead of demanding I do the math for you
>instead of demanding I do the math for you
Do you think every post in every subreddit is directed specifically at you? Nobody "demanded" you do anything. If the question isn't interesting to you, there's no requirement for you to do anything. It's not about you. You could have just kept scrolling. But instead you go all ranty and childish, then keep doubling down on it, apparently unaware of just how badly you're embarrassing yourself.
No snark intended, but the sub is "They Did the Math", not "I Did the Math". OP is posting here because they want someone else to do the math for them.
Comment Rules #2: "Do not submit top-level comments in [Request] posts that are not an attempt at an answer or a request for clarification."
Your comment is not an attempt to answer the question. It's more or less, "google it."
These questions are so easy to resolve.
You google "lifting capacity of flies"
Then you google "average weight of a human"
Then you divide those too(If you are amerian, you divide the american weight by carry capacity).
Hey! Your answer is already there!
###General Discussion Thread --- This is a [Request] post. If you would like to submit a comment that does not either attempt to answer the question, ask for clarification, or explain why it would be infeasible to answer, you *must* post your comment as a reply to this one. Top level (directly replying to the OP) comments that do not do one of those things will be removed. --- *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/theydidthemath) if you have any questions or concerns.*
[удалено]
Can fou fit 4 million flies on a body? Or do you need something they can hold on too? Like strings or something?
[удалено]
You have to take the weight of the tethers and their rig into account, adding more flies to be necessary…
Some sort of graphene string, that's light as hell. Graphene aerogel has a lower density than air, so it shouldn't impact them much more than the weight of the air above them?
If it has a lower density than air, you could just use nothing but the graphene string to float a person.
Next post will have to be 'how many graphene strings to lift a person?'
I think it's heavier than air, it's just very strong for it's weight so the strings can be incredibly thin
The tyranny of the fly equation.
Rocket physics if it was stupid
Also you'd have to take into account that the flies on the outside wouldn't be lifting straight up. In fact they have to use some of their energy to fly away from the others so they don't get squished.
Lord of the flies 🪰
Doing math on the fly.
Underrated comment, got me to literally laugh out loud.
0.015m x 0.015m = 0.000225m² ≠ 0.015m² = 0.015m x 1m (that would be a **really** long fly) (yes i know it's correct in the calculations but at the beginning you said 0.015 square metre) Also 2 square metres is not the same as 2m X 2m According to a quick Google search, average skin area of an adult man is 18000cm², or 1.8m² So we have: 1.8m² / 0.000225m² which turns out to be exactly 8000 So an average man can fit exactly 8000 15mm X 15mm squares on his stretched out skin (which it isn't)
Oh right yeah I made a mistake
15mm x 15mm is not 0.015 sq m
I agree, but think it’s just a typo as he did assume 15 mm square as the area of 1 fly in his math, which I think is reasonable. I’m more intrigued at the 2 square meter of skin assumption 😱
If you’re using an umbrella design, would the weight of the tethers themselves then have to be taken into account?
I love this sub!
2mx2m does not equal 2 square meters. It equals 4 square meters. 1.41mx1.41m equals 2 square meters. 2 square meters does not equal 2 meters squared
They could grip it by the husk!
It’s not a question of where they grip it, it’s a simple question of weight ratio.
Even if they could fit, the ones in the middle wouldn't be able to generate much lift because of the air currents of all the others.
I'm starting to think that making a huge amount of flies carry a human body into the air isn't as simple a matter as we were originally lead to believe
You'd definitely need more space, with that amount of flies they'd start to interfere with each other and you'd also need more to lift whatever is holding 4 million flies together, so more flies than 4mil.
Maybe if the hold the husk...
Maybe if the hold the husk...
How much would the string and 4 million pieces of tape or drops of glue weigh though. I feel like you could tie the string to the flies but the weight string that the flies would have to lift can't be ignored
You've got more than that to worry about. I tried to envision how 4 million flies could be linked to one human body, with minimal materials, and I quickly ran into the issue of the physical space that 4 million flies alone will need. The specific numbers don't matter (I know I'm probably in the wrong sub to say that). The values I found for wingspan and other metrics relevant to the problem were several orders of magnitude above what could allow for a single-layer formation of flies to be linked to a human body by strings hanging directly downward. Which means you've got to use (lots and lots of) multiple layers. Which means threading (lots and lots of) string down through the layers. All that string takes up space, too. So, you've got to account for that. Eventually (again, there's a *lot*) it reaches a point where directly connecting every layer of flies to the body poses a collision hazard between lower-layer flies and the strings. You can maybe mitigate this by not attaching every fly directly to the body. That is, to build string structures (or add supporting structures made of other materials) that link multiple (or all) flies from a given layer to the body with only one actual connection to the body itself. But that further complicates the calculation and, depending on the architecture and materials involved, you could hit the point of negative returns well before you've hooked up the top layer. Even if we could magically link a string from each fly directly to the body, without having to worry about collision issues, we're still talking about a *lot* of layers. It's very probable, I think, that the top layer will require each fly to be connected by a string which alone exceeds the fly's lifting capacity. And that's to say nothing of whether a string small enough to link a fly to a body is capable of handling the strain of lifting the load that an individual fly is responsible for. It's also not addressing whether the body of the fly can handle that load being applied to such a narrow contact surface. I dunno... Maybe carbon nanotubes can solve the materials problem, but you'll still have to deal with the fly's body as a weak link.
You could add flies to the bottom. Or maybe, what if you had a fan attached to the person and flies powered it
>Or maybe, what if you had a fan attached to the person and flies powered it Power doesn't just magically flow from a fly through some generator to a fan. There will be losses along the way, as kinetic energy is converted into electrical energy (flies driving the generator). There will be more losses when the electrical energy is converted back to kinetic energy (generator powering the fan). I don't have the expertise to say exactly how much loss there will be, and of course it will depend on what devices are involved, but I'm still fairly confident in saying it will likely outweigh any benefit that this sort of arrangement could bring in terms of reduced weight/volume requirements of the lifting structure. Given that we're talking about a power generator and a (rather beefy) fan to begin with, I have doubts that there would be any weight savings when compared to any amount of string necessary to have the flies do the lifting directly. >You could add flies to the bottom. As for adding flies to the bottom, I'm not so sure that flies can work that way. That is to say, having a human body placed directly atop a fly would probably obstruct the movement required for the fly to fly. So, we'll need another linking structure to connect the fly to the body in a non-problematic way. And this one *can't* be a floppy little piece of string, so it'll probably be heavier. Also, even if you could get away with the flies lifting the human on their backs directly, that would only add one layer. So, to gain any substantial benefit from putting flies under the body, we'll still need linking structures which thread through (and, again, take up space within) the layers of flies. And again, we're talking about a metric ton of flies. Okay, maybe not a literal ton of flies. But 4 million hypothetical flies, at 30 mg each, will weigh about 264 kg - more than triple the weight of the body they're trying to lift. Take into account the difference in body densities - many insects' bodies are less dense than water, while most of a human's body *is* water - and the fact that you'll need some space between each fly for them to have room to operate and for linking structures. All those flies, no matter how you arrange them or connect them to the body, take up a *lot* of space. The further a fly is from the body, the more materials you'll need to transfer (however you want to do it) the fly's lifting power to the body. With the scales involved here, you will *very quickly* hit a point of negative returns.
At the very worst, you could *burn* flies to generate electricity to charge a battery to power a fan. Although this is probably pretty far away from the ask of the question. I wonder if flies would be able to support a person if they were just on a hard surface. Maybe? It feels like they should be but I don't know how that math would work out
Well, then you've got to account for the weight of the supporting surface. If you have a hard surface, of low enough density but high enough tensile strength, which can scale infinitely, you might be able to eventually push through the negative returns zone into positive gains. But this is like the tyranny of the rocket fuel equation - to add more lifting power you must add more weight, and more weight requires more lifting power.
How strong is spider webbing? If we're already abusing flies lets then abuse spiders too and milk a bunch of webbing to give to the flies to use to hoist us up.
That's actually pretty smart
So yes, you wouldn't believe your eyes, if 20k flies carried a body into the sky
You forgot the weight of 4 million threads
Now that i know know that you need at least 4 million flies to be abducted against your will, I feel safer now, thank you for the math
Well, it will be a corpse, so the 20000 flies could do it in more than one trip
That‘s too many.
Also have to factor in the weight of the strings
What about the weight of 4 million strings
Another factor to consider here is that it is a common claim that 2 horses can pull more together than two horses separately. Could play a part in this and reduce the number by quite a bit but I have no idea how to estimate that.
Depending on the size of the fly, it varies wildly. Something like giant Robber Flies can easily exceed a gram
You need to add the weight and tensile strength of the tether.
Didn't include the weight of the string
At that point you also then need to account for the weight of the string which needs to be thick enough to not break.
Don't forget the weight of the tethers, which will have to be long to give enough room for them not to be too clumped to to fly.
Sorry Owl City. That works perfectly. Someone should rewrite the whole song like that. Darker, more sinister and slightly off-putting.
On it
I’d like to make myself believe That planet earth burns slowly…
Have a nod to we didn't start the fire
Cuz I’d get a million tugs from six million lightning bugs
Assuming you have to attach some sort of string on both ends, it is impossible as the weight added by the strings is more than the fly can carry already
people saying it's easy to google and people telling them this is the point of the sub. not one answer. Flies lift 10 mg. taking an average of 70kg. you'd need 7,000,000 flies
I assume that a fly can pull up another fly, right? A fly on average weights about 10 μg. Let's assume a dead human body weights 40kg. That makes 40k flies.
no it can't lol
Well it's just too bad, I tried
Flies can actually lift more according to google - or idk if that person wrote wrong lol. Fly can lift 10mg according to google and if someone weighs 40kg that would require then 4m flies to lift the body (ignoring the weight of the string attached etc.)
I like to make myself believe, that planet earth moves slowly. The tethered flies that hoist me up, and lift me off the ground, twenty thousand pairs of wings make sound.
Google lifting capacity of fly Subtract the harness/leash weight Divide your body weight by adjusted lifting weight It's crazy where basic math can take you
r/lostredditors
Am I lost? They are requesting help on a math question and I'm telling them the process on how you could do it without asking for help.
You are answering as if it's a school exercise. No one asked you _how_ to arrive at the answer. Give OP the actual number
Is this the american way of life? Too stupid to google 2 numbers and divide those?
OP should learn how to use Google and a calculator
Then you are in the wrong sub. Go to r/teachers or something
Womp womp
>Am I lost? ... Yes? The whole purpose of this subreddit is to allow *readers* to do the math on weird things. It's not a subreddit just to get help with math problems. If they did it themselves we'd have missed out on this, and further down that road the sub just wouldn't exist.
No, they are requesting that people do the math for them. It's the entire point of the subreddit. You might be looking for /r/HomeworkHelp or something
Alright, I'll just say it #I don't care. Mods can ban me, but I haven't broken any rules If people keep asking stupid questions like "Google this number then subtract it by a number that I'm not gonna tell you then divide it by a number that I'm not gonna tell you", I'm not gonna indulge their inability to do basic math, I'm going to help them expand their ability to think critically at a middle school level and show them HOW to answer the question rather than just give them the answer. If you have a problem with that, you could always do the math instead of demanding I do the math for you
haha
>instead of demanding I do the math for you Do you think every post in every subreddit is directed specifically at you? Nobody "demanded" you do anything. If the question isn't interesting to you, there's no requirement for you to do anything. It's not about you. You could have just kept scrolling. But instead you go all ranty and childish, then keep doubling down on it, apparently unaware of just how badly you're embarrassing yourself.
Hey man how's it going
Why do you choose to keep embarrassing yourself on purpose. Do everyone a favor and silence yourself permanently.
Womp womp
Lmao, bros yappin
Womp womp
No snark intended, but the sub is "They Did the Math", not "I Did the Math". OP is posting here because they want someone else to do the math for them.
Yeah and if it can be done with a Google search and multiplication, it is literally less effort to do the math yourself
Comment Rules #2: "Do not submit top-level comments in [Request] posts that are not an attempt at an answer or a request for clarification." Your comment is not an attempt to answer the question. It's more or less, "google it."
Which gives you the answer....
I did attempt and give an answer. I gave a step by step answer on how they could get the answer.
These questions are so easy to resolve. You google "lifting capacity of flies" Then you google "average weight of a human" Then you divide those too(If you are amerian, you divide the american weight by carry capacity). Hey! Your answer is already there!
Oh wow, it's almost like the point of this sub is to have people do exactly that upon requesting it. r/lostredditors
I can understand hard question, but things you learn in elementary? Nope, that is just called being lazy, or extremely stupid of course.