#### puella

##### Popopopopopopopo!
As for this cosplay... The guy playing Void is the one who drew berserk parody manga.

you check the old thread? :'(

His nickname is also Void.

Anyway, recently I talked with him about that cosplay.
He talked much about the DS which they made with special paper.
According to him, much power was needed to weild such just paper DS like Guts does.

This interests me so much..

Then how much power is needed when Guts wields DS arbitraily supposing DS weighs 100kg(220 pounds around)?

I know we can't figure out accurate power but just want to try at least. Unfortunately, I myself can't do it. :(
Scientific access or some clue with understandable basis is highy recommended here if possible.

Get the calculator and pull out your hair, guys. ;D

#### SaiyajinNoOuji

##### I'm still better than you

I could swing it around somewhat controlled but thats just because I'm an ox... ;D As for how much energy is needed... I wouldnt even know where to begin for the formula... meh. ???

#### xechnao

Who said DS weights 100kg?

#### puella

##### Popopopopopopopo!

SaiyajinNoOuji said:
I could swing it around somewhat controlled but thats just because I'm an ox... ;D As for how much energy is needed... I wouldnt even know where to begin for the formula... meh. ???
Yeah, we need some formula including weight, distance,velocity(acceleration), time...etc.
The problem is that I don't know any shit of it. :'(

xechnao said:
Who said DS weights 100kg?
I said "arbitrarily supposing....". it has nothing to do with the actual weight.

#### xechnao

There is no direct answer to your question. When you mean energy you must be asking how much calories Guts can consume each moment.
Well this depends from the exact motion every time as the biomechanincs change constantly in the fighting he does. You can only calculate this abstractivelly thinking of Guts capacity. I would say, because Guts fights till exhaustion, that he dedicates the maximum of his capacity- so you have to check now how much calories a human of his construction can burn till exhaustion of handling DragonSlayer efficiently.
To answer this we have to make an experiment:
First we have to clone ten Guts. Now we are going to give them a DragonSlayer each and let them simulate a fight like Guts does till exhaustion. Then we register how much time each Guts has lasted. Now, asigning a theorical value to Guts potential before the fighting simulation starts, adding the time per effort(that equals the capacity) we must equal the value after the fighting as the base* energy of organism survival[beos] at a given time. So finally it all depends on the time elapsed. If they resisted for one minute (and we are calculating beos at seconds) the answer will be one minute per beos/sec, if they resisted two minutes it will be two minutes per beos/sec.
Adding this to assigned beos/sec of Guts we have the initial energy potential of Guts.

*base=it could be lower but we are interesting in DragonSlayer fighting.

#### puella

##### Popopopopopopopo!
xechnao said:
There is no direct answer to your question. When you mean energy you must be asking how much calories Guts can consume each moment.
Well this depends from the exact motion every time as the biomechanincs change constantly in the fighting he does. You can only calculate this abstractivelly thinking of Guts capacity. I would say, because Guts fights till exhaustion, that he dedicates the maximum of his capacity- so you have to check now how much calories a human of his construction can burn till exhaustion of handling DragonSlayer efficiently.
To answer this we have to make an experiment:
First we have to clone ten Guts. Now we are going to give them a DragonSlayer each and let them simulate a fight like Guts does till exhaustion. Then we register how much time each Guts has lasted. Now, asigning a theorical value to Guts potential before the fighting simulation starts, adding the time per effort(that equals the capacity) we must equal the value after the fighting as the base* energy of organism survival[beos] at a given time. So finally it all depends on the time elapsed. If they resisted for one minute (and we are calculating beos at seconds) the answer will be one minute per beos/sec, if they resisted two minutes it will be two minutes per beos/sec.
Adding this to assigned beos/sec of Guts we have the initial energy potential of Guts.

*base=it could be lower but we are interesting in DragonSlayer fighting.
Good call. Yeah, interesting.
But the problem is that Guts should always consume calories much more than those he got from food. ;D

And... how's the power(something like strength or force)?
I modified the word energy in my topic into power which we calculate with such an unit as N(Newton).

#### xechnao

puella said:
Good call. Yeah, interesting.
But the problem is that Guts should always consume calories much more than those he got from food. ;D
Other than fat, when we eat we also store energy at liver and at muscles. We assume that Guts doesn't stress his costitution so much that he will provoke muscle catabolism because in that case he coud die without modern medical attention.
puella said:
And... how's the power(something like strength or force)?
I modified the word energy in my topic into power which we calculate with such an unit as N(Newton).
Power and strength in classic physics are two different measures. What exactly do you want to calculate? Make two examples using two confrontable conditions that show the diversity factor you want to calculate and then maybe I can help.

#### Mizar

SaiyajinNoOuji said:
I could swing it around somewhat controlled but thats just because I'm an ox... ;D
I don't think so, you may be able to lift 100 kg (=222 lbs) but I doubt you can hold a 7 feet long object of this weight even an inch from the ground if you are holding it at the end of the object. The amount of strength you need is much bigger than if you just lift it up, this is because of torque. I think this is what Puella wants to know.

Well, in order to calculate this we can use the following formulae:

- F1 x d1 = F2 x d2 (conservation of quantity of Work, where d is the distance from the fulcrum)
- F = force in kg (multiply by 9.8 to get Newton)

d1 = distance from origin of F1 to the fulcrum
d2 = distance from origin of F2 to the fulcrum
F1 = Guts needed amount of force to keep the DS in a state of equilibrium
F2 = Force as a result of gravity working on the DS = weight DS

Now we need to make a few assumptions, like at which point Guts is holding the DS, or in other words where the point of rotation (the fulcrum) is at. So let's assume the fulcrum is at one feet from the edge of the 7 foot blade. Now we need to estimate the point at which Guts is applying the force to be able to swing his sword around the fulcrum. To keep things simple let's assume this is also at exactly one feet from the fulcrum (the edge of the sword).

Ok, let's do a few calculations now. :)

F2 = 100 kg
d2 = 7/2 - 1 = 3.5 - 1 = 2.5 feet
d1 = 1 feet

F1 x d1 = F2 x d2 ==> F1 = (100 x 2.5)/1 = 250 kg (556 lbs, 2450 N)

So Guts needs to exert a force of 250 kg in the opposite direction of F2 with his lower arm to be able to keep the sword in equilibrium. But that's not all, his other hand is functioning as the point of rotation (fulcrum) and needs to exert a strong amount of force to counter the force of gravity and the force Guts is exerting with his other hand. I'm not sure how to calculate this, but I think it's close enough if I say this force is equal to F2 + F1 = 350 kg (!!) (778 lbs)

To conclude, these calculations show that Guts needs to exert an amount of force of over 250 kg with one arm/hand to be able to swing the sword, and 350 kg with his other hand in order to keep the balance. Of course I do realize that in reality the dynamics of swinging a sword are not quite as simple as I'm portraying here, but I think it gives a general idea: nobody existing in real life could swing this sword. ;)

#### Majin_Tenshi

##### The can opener went bye-bye...
puella said:
Then how much power is needed when Guts wields DS arbitraily supposing DS weighs 100kg(45 pounds around)?
about the right conversion factor, but the wrong way. Its more like 220 lbs.

#### puella

##### Popopopopopopopo!
Mizar said:
I don't think so, you may be able to lift 100 kg (=222 lbs) but I doubt you can hold a 7 foot long object of this weight even an inch from the ground if you are holding it at the end of the object. The amount of strength you need is much bigger than if you just lift it up, this is because of torque. I think this is what Puella wants to know.
Wow, good job, Mizar! This is very good attempt.
But what if the speed is concerned?
We need to set arbitrary speed?

Majin Tenshi said:
about the right conversion factor, but the wrong way. Its more like 220 lbs.
haha. Yeah so strangely you and I posted at the same time.
After I corrected the number, I found yours.
Damn, I often miscalculate it. :-[
Thanks anyway.

#### xechnao

Shit,
the energy each muscle has to put changes dramatically if the geometric disposition measures regarding Guts skeleton and dragonslayer in their place in the gravity field change even slightly.
Now, regarding that the whole skeleton-dragonslayer system has to maintain all internal relative points constantlly at relative speeds zero we could calculate how much force the muscles have to apply in order to maintain this balance of the system in the gravity field at its exact position. Because all muscles work together it makes sense start to work like this.
Like this we calculate the dynamic energy of the stance in the gravity field. Pay attention that there is a rigid surface Guts is standing upon but it is not included in the system although it has a mechanical effect of dynamical torsion on Guts (especially joints) because is considered a small extra add to the whole problem.

But after we calculate the total dynamic energy regarding the value we have given at the gravity field at the point Guts is, we must see if it is possible this to be accomplished by Guts individual muscles because each muscle doesn't collaborate exactly as an arithmetic value because muscles have different geometric places. So it is possible that to maintain this stance some muscles don't have the necessary force. This means that the stance would not be possible to achieve by Guts.

#### Mizar

puella said:
But what if the speed is concerned?
We need to set arbitrary speed?
Speed is irrelevant (neglecting air-resistance), acceleration however, isn't (check Newton's first and second law of Motion). If you want to include the acceleration speed of the DS into the equation it will make things a bit more complicated though. The needed amount of force to reach a certain acceleration depends on the direction of the sword and I'd have to make new calculations with a new rotation point centered on Guts himself. Maybe I could do some calculations with Guts swinging his sword horizontally or vertically. I'll think about it. ;D

However, it's impossible to calculate the exact force Guts is using while swinging his sword (see xechnao's reply, lol), it's too dynamic and there are too many variables to consider. I can only give a rough estimation like this, but it's fun nevertheless. :)

#### xechnao

Mizar said:
Shit, I understand I have used some very complicated and bad english. If there is some point you need more clear just ask.

#### Mizar

xechnao said:
Shit, I understand I have used some very complicated and bad english. If there is some point you need more clear just ask.
No no, it's ok, I just thought it was funny how you went into full detail about the 'skeleton-dragonslayer system' and the geometric positions of the muscles and such. I wasn't trying to ridicule your post or anything. :)

#### puella

##### Popopopopopopopo!
Mizar said:
Speed is irrelevant (neglecting air-resistance), acceleration however, isn't (check Newton's first and second law of Motion). If you want to include the acceleration speed of the DS into the equation it will make things a bit more complicated though. The needed amount of force to reach a certain acceleration depends on the direction of the sword and I'd have to make new calculations with a new rotation point centered on Guts himself. Maybe I could do some calculations with Guts swinging his sword horizontally or vertically. I'll think about it. ;D
Well, yeah it will be much more complicated. But you said you'd think about it? Can I expect? ;D

However, it's impossible to calculate the exact force Guts is using while swinging his sword (see xechnao's reply, lol), it's too dynamic and there are too many variables to consider. I can only give a rough estimation like this, but it's fun nevertheless. :)
Of course, it's impossible to get the exact force but what's wrong with a rough estimation?
The attempt itself is worth.

xechnao said:
Shit,
the energy each muscle has to put changes dramatically if the geometric disposition measures regarding Guts skeleton and dragonslayer in their place in the gravity field change even slightly.
Now, regarding that the whole skeleton-dragonslayer system has to maintain all internal relative points constantlly at relative speeds zero we could calculate how much force the muscles have to apply in order to maintain this balance of the system in the gravity field at its exact position. Because all muscles work together it makes sense start to work like this.
Like this we calculate the dynamic energy of the stance in the gravity field. Pay attention that there is a rigid surface Guts is standing upon but it is not included in the system although it has a mechanical effect of dynamical torsion on Guts (especially joints) because is considered a small extra add to the whole problem.

But after we calculate the total dynamic energy regarding the value we have given at the gravity field at the point Guts is, we must see if it is possible this to be accomplished by Guts individual muscles because each muscle doesn't collaborate exactly as an arithmetic value because muscles have different geometric places. So it is possible that to maintain this stance some muscles don't have the necessary force. This means that the stance would not be possible to achieve by Guts.
Good. Then we might get down to some kinetics? ::)

#### xechnao

puella said:
Then we might get down to some kinetics? ::)
Hmmm, kinetics introduce the concept of space change in respect of time. Here I will direct you to my first apply about calories. You see, as Guts dances around you must ask yourself if you want the calculation of Guts energy at a given photographic moment or of the energy he cosumes at a time period (for example a second or half an hour). In the first case it depends from the moment because fact is that his total energy is not the same at all the moments as far as his muscle effort. This is because although the kinnetic energy+dynamic energy remain constant due to the principle of the conservation of energy
as far as the gravity field is concerned, to be precise you need to calculate each moment's bioenergy input which changes by what Guts dancing accelerated move is doing. This is not that much, but it is something.
So you have to define this before you can calculate. Now, this is not very difficult to extract. For example let's talk about the acceleration Guts needs to develop for beating a metal armour with DragonSlayer or for knocking back a person that weights 80 kg. In the first case for example we need to know with what speed does DragonSlayer need to travel to beat the armour. If we know this we can calculate the acceleration needed from 0 to that speed. This way we could calculate more or less how much energy a thrust of Guts takes him. More or less because as Guts skeleton and DragonSlayer move, the baricenter of the system changes and thus changes the bioenergy input for his stance.
Do you remember before that I said there is a rigid surface Guts is standing upon? Now there is an application of force at Guts' baricenter from the rigid surface he is standing upon against the gravity at the baricenter point. If the force is less than Guts' weight, Guts will start to fall and will have to use some kinetic energy to rebalance himself.
Assuming this problem won't come at hand calculating the kinetic energy for penetrating an armour with dragonslayer & the time Guts needs to complete the motion( depends from his distance from the armour as this is the time he needs to reach the armour) that moltiplicates the dynamic energy he consumes at the unit of time for his stance can give the total amount Guts needs for the thrust.

#### puella

##### Popopopopopopopo!
I'd say we can say the monsters killed by Guts are actually not so much "simply being cut off" as "being broken or bursted" considering such a huge power of Guts.
For this matter, once again I am reminded of the line "It is more like an iron hammer than a sword..."

But the problem is the monsters don't have common skin as the other creatures we can see in the world.
For example, Grunbeld has corundum skin.
Should we suppose the skin of monsters be close to some metal in terms of toughness? ::)

#### xechnao

puella said:
I'd say we can say the monsters killed by Guts are actually not so much "simply being cut off" as "being broken or bursted" considering such a huge power of Guts.
For this matter, once again I am reminded of the line "It is more like an iron hammer than a sword..."

But the problem is the monsters don't have common skin as the other creatures we can see in the world.
For example, Grunbeld has corundum skin.
Should we suppose the skin of monsters be close to some metal in terms of toughness? ::)
In my example above I calculate enough power to penetrate armour starting from zero speed. In the process I made the experiment which I throw DS against the armour at various speeds and write down the one that achieves the desired effect so I can calculate the acceleration from zero to that speed. You should repeat this against the surface you want, throwing always DS against, till you find the speed that matches your desired effect and then calculate acceleration from zero to that speed. Now Guts has to hit the surface with the same way (as for the traietory or direction of movement) as in the experiment DS hits the surface. This is just the factor of skill and is not something that we are dealing now.

PS your desired effect might be something from "simply being cut off" as to "being broken or bursted: it depends from you. You have to define this as a standard, calculate speed, then acceleration or kinetic energy and go on as said above.

#### xechnao

Last night I went to bed, I was thinking about it and then it struk me that I was not precise at all.
In a position-stance the skeleton remains in its place due to skeleton itself, joints and muscle. Although the dynamic energy Guts has, is true that it remains the same but it's production is shared among the above factors. From the above factors skeleton and joints can be safely considered to have a constant value of energy consumation in every position Guts assumes because they are much too stable(think of rigid) for any positioning of Guts in the gravity field. But muscles having a much higher elastic quality factor need a lot of more energy to hold the same weight for example a bone or a joint holds. Thus we need to calculate what percentage of the weight lifted is due to skeleton-joints and what due to muscle. The only thing we are interested eventually is the muscle percentage factor because the bone-joint factor doesn't change the energy input of bones and joints as we have said about above. So in a standing position that the weight is hold mostly by skeleton and joint resistance Guts won't consume lost of bioenergy to stay in place. But in a more weird stance, where muscles are more involved Guts consumes a lot more bioenergy. Thus we have to check for example how the baricenter weight is distibuted along the lifting systems: skeleton-joints and muscles. If the baricenter weight has a 35% lift due to muscle this will mean a lot more bioenergy consumption for Guts instead of the case it was 10% due to muscle.
Further more the muscle energy machine mechanism is far from the perfect Carnot machine ideal. It has a lot of energy loss due to heat. Thus the more muscles work the more heat Guts will produce and lose and the more bioenergy he will consume: he even may consume enough to overheat himself and apply a cooling mechanism that is sweating (that the mechanism itself needs even some more energy to work).
So, you have over the standard omeostatic mechanisms you have to calculate all the above when somebody is using his muscles to lift a weight, to see how much energy he consumes.
It is not that hard if you know the data. Muscle contratction let's say needs A energy at a weight unit and X% is the percentage of weight that muscles contract to lift. When a muscle contracts let's say he produces B heat at a weight unit it contracts to hold. When the body is at 36+B Celsius temperature let's say that it produces C energy to let the heat escape.
So it would be something like
AxX% + BxX% + C=Energy loss for the stance

Now in practice the cooling mechanism should drop the heat down and not be more necessary but if Guts continues his stance more heat is going to be produced. So the cooling factor is not constant in time. You have to apply in the time function the heat prosuction variable and check the area of the function. All the rest is solved through basic mathematics.

#### roberto999

##### The Black Chick of Darkness

Mizar said:
I don't think so, you may be able to lift 100 kg (=222 lbs) but I doubt you can hold a 7 feet long object of this weight even an inch from the ground if you are holding it at the end of the object. The amount of strength you need is much bigger than if you just lift it up, this is because of torque. I think this is what Puella wants to know.

Well, in order to calculate this we can use the following formulae:

- F1 x d1 = F2 x d2 (conservation of quantity of Work, where d is the distance from the fulcrum)
- F = force in kg (multiply by 9.8 to get Newton)

d1 = distance from origin of F1 to the fulcrum
d2 = distance from origin of F2 to the fulcrum
F1 = Guts needed amount of force to keep the DS in a state of equilibrium
F2 = Force as a result of gravity working on the DS = weight DS

Now we need to make a few assumptions, like at which point Guts is holding the DS, or in other words where the point of rotation (the fulcrum) is at. So let's assume the fulcrum is at one feet from the edge of the 7 foot blade. Now we need to estimate the point at which Guts is applying the force to be able to swing his sword around the fulcrum. To keep things simple let's assume this is also at exactly one feet from the fulcrum (the edge of the sword).

Ok, let's do a few calculations now. :)

F2 = 100 kg
d2 = 7/2 - 1 = 3.5 - 1 = 2.5 feet
d1 = 1 feet

F1 x d1 = F2 x d2 ==> F1 = (100 x 2.5)/1 = 250 kg (556 lbs, 2450 N)

So Guts needs to exert a force of 250 kg in the opposite direction of F2 with his lower arm to be able to keep the sword in equilibrium. But that's not all, his other hand is functioning as the point of rotation (fulcrum) and needs to exert a strong amount of force to counter the force of gravity and the force Guts is exerting with his other hand. I'm not sure how to calculate this, but I think it's close enough if I say this force is equal to F2 + F1 = 350 kg (!!) (778 lbs)

To conclude, these calculations show that Guts needs to exert an amount of force of over 250 kg with one arm/hand to be able to swing the sword, and 350 kg with his other hand in order to keep the balance. Of course I do realize that in reality the dynamics of swinging a sword are not quite as simple as I'm portraying here, but I think it gives a general idea: nobody existing in real life could swing this sword. ;)
You are speaking about a single blow. Now try to calculate the amount of energy necessary to swing it all the night...however I don't think that dragonslayer weighs 100 kg. This man weighs about 90-95 kg #### Darok

##### Melancholy (Holy Martyr)
Iron is rather dense. I did a few calculations on the DS's weight (assuming it is Iron, and Guts is 6'2", thus from handle to blade's end the DS is 6'5") and got 420~ lbs, about 190 KG. Granted, I didn't take into account the narrowing of the "blades" but I don't think that would knock off half of the weight.

#### Mizar

roberto999 said:
You are speaking about a single blow. Now try to calculate the amount of energy necessary to swing it all the night...
Actually I was speaking about the amount of force needed to hold the DS horizontally in a perfect state of equilibrium, I hadn't even come to the actual movement of the sword yet. But I've been working on those calculations and will post them when I'm done. :)

#### Kart

##### Resident /b/tard
also, the DS is hollow for the most part, the dark idea in the middle is dig out to make it lighter.

#### puella

##### Popopopopopopopo!
roberto999 said:
You are speaking about a single blow. Now try to calculate the amount of energy necessary to swing it all the night...however I don't think that dragonslayer weighs 100 kg. This man weighs about 90-95 kg But I think Guts is taller than Arnold. So he is more than 100kg I guess.....

** Anyway, I thought about instantaneous power when Guts wields DS. It will be very huge. I'd say such a power is almost equivalent to the power you get when trying to lift up a car?
What do you think? More? or less?

I mean I want to figure out concretely when/how such a power works in our life. ::)

#### puella

##### Popopopopopopopo!
Ah some Korean guy tried to calculate Guts' power. Yeah, I posted the same topic there, too.
He arbitrarily supposed DS weigh 40kg.

Damn his estimation is fucking good but I can't tranlsate such special terms and professional explanation into English. :(

Anyway, his conclusion is the power comes to 320000N~480000N.

** Here's my poor rough summary of his calculation.

Why he estimate DS weighs 40kg around?

Specific Gravity of steel : 7850kg/m3
Width of DS: 25cm-30cm
length: 170-190cm
Thickness : 1cm(the blade part excluded)

Total volume of DS :25x170x1~ 3x190x1 ---->4250cm3
----> 33.2kg - 44.5kg(weight)
He said this was almost as heavy as 1m of H-beam which we often use for construction.

If the thickness is 1.5cm, the weight will come to 60kg.

Arbitrarily supposing the length is 180cm ,the weight is 40kg and the distance from Guts' wrist to DS is 90cm, then the force(power) comes to 36kg*m.
Considering the average muscular strength of baseball players is 270N*m(27kg*m), we can say Guts should take much more power than them even just holding up DS.

torque

it is 3.6 when he just holds up DS, so we need to calcualte another torque when he is wielding DS.

speed

he just got straight speed not rotation one.
and the extent of wielding DS is 2-3m considering Guts can cut off 3-5 at a time.

Speed and acceleration of DS

Speed of nerve reaction of normal ppl is 0.25sec(he was not sure of this) but no doubt Guts has much faster one.
So he supposed the speed of Guts be less than 0.1sec.
It could come to around 0.01sec because Guts has fucking fast speed.
If it is 0.01sec, speed will be 200-300m/sec, which is almost equivalent to the speed of sound.  Anyway, he got 0.05sec for Guts' speed of nerve reaction.
Then speed is 100-150m/sec, acceleration is 8000~12000m/s².

His final calculation

F=ma
F: 320000~480000kg*m/s² --->320000N~480000N

This force(impact) is when some stuff weighing 32000~48000kg jump from 1m tall building, of course by natural falling.

*** I have to say I don't know much about physics so my translation of the special terms is pretty bad. Feel free to correct the terms , please.

Anyway, isn't it just great? 8)