E = MC^2 debate and laws of physics

[bleuless]

i remember reading it in articles a few times about how E =! MC^2 (energy does NOT equal to mass times acceleration square)

can someone shed some more light on this? possible a good prove or hypothesis about this.

i need this because my friend does not believe it, but all i am saying is i've read about it before and it certainly is there.

there are a few instances that the E=MC^2 simply does not hold true and can not be used to solve certain " <insert choices>"

thanks in advance guys.

 

[Shalmanese]

I doubt you would have read anything like that from a reputable source. AFAIK, nobody has seriously challenged the e=mc^2 relationship yet

 

[Tichio]

As far as I know E=MC2 had never been proven wrong,

however I think Stephen Hawkings has proposed that in the centre of a black hole the normal rules of physics start to break down and that E=MC2 could be broken under these circumstances.

Hope this helps

 

[Mark R]

Probably not what you want, but:

E =mc^2 only holds for objects at rest, as it fails to account for kinetic energy.

E=mc^2 is actually an abbreviation of the equation E = m (c^2 / (v^2-c^2))

 

[JSSheridan]

There is also the case where you may have a particle that doesn't have any mass. According to E=m*c^2, massless particles wouldn't have any energy, but they obviously do. The energy for a massless particle is dependent on the speed of the particle and Planck's constant, h. E=m*c^2 isn't the most general equation for energy. The most general equation is,

E^2 = (h*c)^2 + (m*c^2/([1-(v^2/c^2)]^(1/2))^2.

c: Speed of light, 3.0x10^8m/s, massless particles always have speed, c.
h: Planck's constant, 6.626x10-34 Js

More than you'd ever want to know

Peace.

 

[bleuless]

in other words, E=MC^2 does not hold true on certain levels, but most of the time it is true?

 

[RossGr]

mc^2 always represents the rest mass energy equivelent of any particle. This is the energy that is released during nuclear reactions, such as those which run our nuclear power plants and the enegy unleashed by a nuclear weapon. That much is always true, it does not however represent the total energy of a massive particle (that is ANY partical with mass) , that will be found in some of the equations given above. If you wish to find the equivelent mass of a photon, simply set its energh (h nu) = mc^2 and solve for m, what does this mean? not much really, it will give you an indication of how the photon will act as it passes a massive body, but do not be fooled, it is NOT a true picture of the actual situation, that can be found only in the math of General Relativative.

i remember reading it in articles a few times about how E =! MC^2 (energy does NOT equal to mass times acceleration square)

This is a serious misstatment, E = mc^2 does not say ANYTHING about acceleration. c is the speed of light, this is a conversion factor and should not be seen as a dynamical statement. The correct statement is mass time speed of light squared. Perhaps you are confusing this with Newtons law F=ma, Force = mass times Acceleration. There is a very big difference.

 

[bleuless]

well said, now i get it.

but what i read actually contradicts this... i only wish i had a better memory of it.

how about this, if all particles are moving (atomic or subatomic level) constantly, there is NO static mass, hence the energy equation has to be the kinetic one not the typical E=MC^2.

realitivity works in a weird way, when mass is great, it appears to be static. but nothing is actually static. yet, the great mass uses the static equation. will the kinetic equation work on a static object?

does anywhere where realitivity actually causes contradictions? i think this is where i've read about the problem. universe is of such great size with all these subatomic particles, there's got to be some phenomenon where things breaks down.

 

[RossGr]

The key word in relativity is.... relative.. If you are at rest with respect to a body, then you measure a rest mass. As long as you are in the same frame of reference then, time, length and mass will measure consistenly. Your velocity relative to other bodies is inmaterial.
edit:
Be very careful applying relativistic concepts to qunantum mechanical systems, that afterall is the goal of the GUT. Currently General Relativity cannot be formally linked to quantum mechanics.

 

[jarsoffart]

I remember hearing that some scientists have proved it's closer to "E=MC^3." My source could be wrong though. I forgot my source too. haha

 

[RossGr]

C is not as constant as you think and so in theory the equation could be wrong although we all assume C is constant.

Easy to say, hard to porve. Meanwhile you sit typing at a computer that relies upon the constancy of c to function. Go ahead, doubt, but, to jump on a bandwagon of the newest pet theory can be hazarous, remember, cold fusion and Jon Schoon.

Personally I'll stick with Maxwell.

 

[rimshaker]

Originally posted by: RossGr

C is not as constant as you think and so in theory the equation could be wrong although we all assume C is constant.

Easy to say, hard to porve. Meanwhile you sit typing at a computer that relies upon the constancy of c to function. Go ahead, doubt, but, to jump on a bandwagon of the newest pet theory can be hazarous, remember, cold fusion and Jon Schoon.

Personally I'll stick with Maxwell.

well, he might be right. Right now some european physicists are questioning the absolute constant of C. It might turn out that the speed of light is also affected by relativity, which would totally make E=mc^2 useless.

 

[RossGr]

Guess you need to read the last sentence of my post, it was directed at that bit of recent headlines. Considering the fate of the work done by Jon Schon, I think this will receive very close scrutiny, further, It is not clear what effect it would have. I am not sure why it would invalidatd relativity. Clearly, if it is changing, it is changing so slowly that it is a constant for the duration of mankind. I may mean an adjustment to the current guesses at the size of the universe, but that gets changed every few weeks anyway.

 

[grant2]

It is my understanding that C = speed of light in a vacuum...

It has long been known that light slows through matter (such as water) .. which is why your straw in that glass appears bent.

 

[lukatmyshu]

Even though all particles are in motion, the Kinectic Energy of them is fairly negligible compared to the energy due to m*c^2. So (like most all laws of physics) it's a fairly good approximation ... like PV=nrt is just a fairly good approximation in most cases, but it's not actually true.