Kinetic Energy for Faster than Light speed

[Ugarik]

I'm trying to find any logical reason not to allow calculating kinetic energy using 1/2mV2 formula for FTL speed that would be consistent with our wiki standards and it seems I can not find any.

Kinetic Energy Feats page says: That is because the kinetic energy of an object, using the correct physical description through relativistic mechanics, would require infinite energy to reach the speed of light, and for objects above the speed of light the equations wouldn't return real values There are two reasons think this makes no sense

1. We can not appeal to the real-world physics
After this thread we all came to the conclusion that we can not invalidate jumping calcs because real-life physics works differently. Some people even used FTL movement as an example. This is also the reason why we separate Speed, Strinking Strength and Lifting Strength of a character despite those things are tightly bounded by Newton's second and third laws of motion.

If FTL movement is available in a verse and we never saw such events as relativistic time dilation, relativistic length contraction nor relativistic-addition of velocities we pretty much have enough evidence that relativistic physics can not be applied and mass does not increase as well. If mass does not increase. acceleration to the speed of light will not require infinite amount of energy. Hence if the general concept "The faster it moves, the harder it's gonna hit you" still work, we should use KE = 1/2mV2 formula

2. We always ignore the Theory of Relativity unless it's kinetic energy
The very base principle of the theory of relativity is that the speed of light is the same for all observers, regardless of their relative motion or of the motion of the light source. It means that no matter how fast a character is able to move, the actual light will always blitz them. Obviously it directly contradicts the Laser/Light Beam Dodging Feats page.

Furthermore, if character A can fight at 60% SoL and is rated as Relativist+ and then we see a Character B blitzing them by moving 20 times faster. Well as I can tell the Character B will immediately be considered 12 times faster than light (FTL+) but according to the Theory of Relativity, character B should only be 99.91% SoL (still Relativistic+). But despite the theory of relativity character from Magi, Dragon Ball Z, Toriko and many more got their FTL rating from blitzing Relativistic characters and nobody is questioning that, including me. (no FTL dragon ball until super lol)

With all that I don't see any logical reason not to use KE = 1/2mV2 formula

Posible Counter Argument
Even if we can see that relativistic physics does not work in a particular verse why are you suggesting using KE formula that had been proven to be wrong by Lorentz almost 100 years ago?

KE = 1/2mV2 formula is correct. It has been empirically verified that the kinetic energy of a moving body is proportional to its mass and square of its speed. People seem to forget is that in relativistic physics mass of an object is not constant but is increasing as the speed gets closer to the SoL. Then we see that a character is approaching the speed of light and we can not see any relativistic time dilation, it's safe to assume that the character's mass remains the same. With all that KE = 1/2mV2 formula works just fine.

 

[DontTalkDT]

Oh cool, time to shoot this down again.

1. The 1/2*m*v^2 formula is outdated for 100 years now. Using it for simplicity is one thing, but in the end it is not better than a random made up formula. We might as well use other pieces of pseudo physics that some ancient civilizations used.

This is in no way comparable to the jumping thing. Even if you magically prevent flying off, distance over time is still a thing that applies.

2. We generally don't ignore relativistic stuff, unless we know it clearly doesn't apply.

And if it doesn't apply we don't use anything more than basic distance over time considerations, which relativity doesn't really change.

( And if you are 0.6c and another dude is 20x faster than you relative to the same observer than you are FTL in relativity as well.)

3. No it isn't correct. Even at low speeds it was always wrong. Barely one of countless good approximations to how things really work. And of course was obviously never verified as a good approximation for anything happening at high speeds.

If a verse doesn't follow physics it's not like it would necessarily follow a special kind of outdated physics either. We may as well invent a new physics for each verse to explain the countless times virtually every fiction breaks actual physics.


So yeah, I am firmly against using wrong physics.

 

[Ugarik]

1. 1/2mV^2 does not work for near speed of light because of the significat mass increase and time dilation that happen at relativistic velocities. If we can clearly see theory of relativity is not a thing in a particular verse we can safely assume there is no mass increase nor time dilation, therefore 1/2mV^2 works just fine.

2. "And if you are 0.6c and another dude is 20x faster than you relative to the same observer than you are FTL in relativity as well". Then why do we consider speed relative to the stationary observer if you are the one getting blitzed? 0.6c character will always be speed blitzed by 0.998c no matter how close their speed relative to a stationary observer is

3. How can this formula be wrong assuming time dilation and mass increase do not occure?

 

[DMUA]

I didn't have too strong of an opinion going into this but DontTalk does have some good points

 

[AlexSoloVaAlFuturo]

Did I just readd a joke from Uga? :fire:

Uh, well, I don't really have something in mind to say; the vastly mayority fiction doesn't follow the real life rules, while some of them make references to it.

It is doubtful to scale or calc the KE with FTL speeds for obvious reason, at least in my eyes. I can agree with both Ugarik and DontTalkDT regarding these issues; it is not like a series will say that all the characters have infinite energy because they are FTL and even if they say so we probably won't acccept such statement for xyz reasons, but at the same time fiction does whatever it wants, so to use something we need to look at each franchise case by case to know what we can apply and what not.

So neutral.

 

[DarkDragonMedeus]

I was asked to comment here, even if it's been inactive for a long while, but I'm leaning towards agreeing with DontTalk that the Theory of Relativity is a super outdated formula. First of all, most theories of relativity assumes the speed of Light is technically Infinite speed. The theory suggests moving at light speeds gives the object moving perceived as time being frozen while everyone else views their speed as instantaneous. Giving the illusion that they move at infinite speed. And that everything FTL travels back in time, similar to what Immeasurable speed characters can do.

However, these theories have been dated ever since the speed of light has an official calculation. 299,792,458 m/s is clearly a finite number. So it doesn't make sense for Speed of Light characters and above to be assumed to generate infinite energy. And plugging in FTL feats into a KE calculator is pretty arbitrary unless there's specific statements such as The Flash for instance. And stuff like planets and stars exploding at FTL feats, not sure how to handle them; but them generating Interstellar and above sized explosions would still be something.

I'd say they need to be analyzed case by case, but in the general consensus I'm with DontTalk here.

 

[KLOL506]

I'm also in agreement with DT here.

 

[Ugarik]

@Medeus

I see. In that case should we note in the Speed page that relativistic velocity composition should be ignored. Because blitzing even 0.999c character by any degree is still relativistic+ with real world physics.

Also what is your point no using relativistic kinetic energy formula in verses like DBZ. I mean this formula assumes mass increase and time dilation while we can clearly see those relativistic events don't exist in the verse in question.

 

[KLOL506]

Frieza's Planet Vegeta calc doesn't use the relativistic formula.

 

[KLOL506]

And Piccolo's moon-busting calc also won't be using speed for the explosion anymore.

 

[DarkDragonMedeus]

Neither one of the calcs actually used the Relativistic calculator actually; the Moon busting one used Potential energy, while the Planet Vegeta one uses the standard calculator.

 

[KLOL506]

I was about to say that.

Cell's solar system feat also doesn't make use of the relativistic calculator and we actually do have a formula for destroying realms across a solar system and such.

 

[KLOL506]

Basically what we're doing now is fine, we already go with a case-by-case basis for stuff like this I think.

 

[DarkDragonMedeus]

Cell's feat uses inverse square law required to destroy the sun via an omni-directional explosion where the epic center is the Earth's starting location. So that's fine.

 

[KLOL506]

Yeah something like that, it doesn't use speed at all.

 

[The_Calaca]

If I understood this correctly, you don't necessarily need to be FTL to blitz a 0.999c character, right?

 

[KLOL506]

That's not exactly what this thread is about tho

 

[The_Calaca]

I know, but I was asking because I'm not getting that part of the argument.

 

[Ugarik]

Yes, you don't need FTL to blitz relativistic+

 

[The_Calaca]

Good to know. Thank you.