Lets come back to this: One Piece downgrade thread

[Floxy178]

Again, how are you saying something so wrong about something as basic as center of mass.
Here its definition: "The center of mass is the unique point at the center of a distribution of mass in space that has the property that the weighted position vectors relative to this point sum to zero.".

It is all about distribution. Its position changes depending on the shape of the object.

But this really turned into me trying to explain basic concepts.

Look, just google how to calculate kinetic energy in circular motion and look at the results. Every single one will use classic KE formula with center of mass.

I gave 3 sources and you are still using your faulty example as a reason to dismiss them. I really don't want to argue with you any longer.

I already showed that using it gives different result also explained why. Explanation wasn't even necessary as it just gives a lower result than it should:

for example rotating rod around its end will be mv²/8 for linear KE and mv²/6 for rotational.(v here is speed of its rotating end)

Also I didn't say that mass center doesn't account for mass distribution, just linear Ke formula doesn't do this. It treats object as point object at its mass center which is the reason why you can't use it for rotational motion.

If you think that it does, then you should also accept that a rod spinning around its center has 0 KE

 

[Floxy178]

Saftirix is correct, and this discussion is a waste of time.

The fist itself looks almost like a ball, just use its center as the center of mass, and use it to find the distance it moved, no need to get too complicated.

Well, I'm arguing not about which one to use, but which one is correct. I agree that it's a waste of time.

Both can be found just by putting values into formula so I don't understand why linear KE's use is preferred despite being incorrect.

 

[Floxy178]

Anyway, why don't we consider forearm's mass too?(if I'm not mistaken it wasn't calculated)

 

[Damage3245]

Anyway, why don't we consider forearm's mass too?(if I'm not mistaken it wasn't calculated)

It looks like it's included to me.

 

[Floxy178]

It looks like it's included to me.

It looks like volume of elliptical cylinder with taking fist to wrist distance as height and forearm's length/width parameters for finding area of ellipse. Then using hollowness. Here volume of fist was found but I don't understand why forearm's width was used.

 

[Vzearr]

I can adjust my calc to include the speed at the center of mass and its kinetic energy later. However, I wanted to discuss the sheer inconsistency of Luffy's fist size:


If the size of Luffy's fist isn't consistent, then a mass or speed can't be found for kinetic energy, as using a different images would yield completely different results. Could anyone provide some insight into which image to use for the size of his fist? I understand that anime studios aren't consistent with sizing, but which image would be the most reliable (if any)? I'd assume it would be the second-to-last image in the Imgur album I linked, as the last image only shows the width and height of his fist, not the giant bubble behind it. However, the size of the fist in the second-to-last image is contradicted a few seconds later by the final image in the album, so I'm a bit lost.

Bump.

 

[Floxy178]

Since we scale fist's size from a part of itself, does size difference between Kaido and fist mean anything? Or you're saying its parts are inconsistent with each other?(like forearm being bigger ore smaller in different frames when we scale it from finger)

If there isn't a problem with second one it should give same result and any of them can be used I think.

 

[Therefir]

Bump.

KingTempest used the second to last image to measure the fist length for the calc, so I recommend you use that one as well to find its center of mass.

With the final image we can't even see the actual length of the fist, it's just a picture of its front part, so we couldn't use it either way.

 

[Floxy178]

One Piece: Gomu Gomu no Bajrang Gun Recalc

vsbattles.fandom.com

I made an end with linear KE as suggested and another one for rotational just in case

 

[Shadow_x007x]

One Piece: Gomu Gomu no Bajrang Gun Recalc

vsbattles.fandom.com

I made an end with linear KE as suggested and another one for rotational just in case

Did you forget to calculate the force? Or do you do it in another calc?

 

[Floxy178]

Did you forget to calculate the force? Or do you do it in another calc?

Yeah, I forgot, probably will do 2 methods for this