E=mc2 — Wikipédia
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Sculpture de « E=mc^{2} » exposée au Walk of Ideas à Berlin en 2006.
L’équation E = mc^{2} (lire « E égale m c carré » voire « E égale m c deux ») est une formule d’équivalence entre la masse et l’énergie rendue célèbre par Albert Einstein avec sa publication en 1905 sur la relativité restreinte.
Elle apparaît en 1900 chez le mathématicien et physicien français Henri Poincaré dans un article La théorie de Lorentz et le principe de l’action et de la réaction^{[1]} où il développe certains principes de déformation de l’espacetemps qu’il appelle relativité, puis en 1903 dans la thèse peu médiatisée d’Olinto de Pretto.
Cette fonction signifie qu’une particule de masse m isolée et au repos dans un référentiel possède, du fait de cette masse, une énergie E appelée énergie de masse, dont la valeur est donnée par le produit de m par le carré de la vitesse de la lumière (c).
Cette formule de transformation, qui est celle de la fusion nucléaire et de la bombe atomique, a fortement marqué les esprits car elle met en évidence que, du fait de l’énormité du facteur c^{2}, une perte de masse même petite à l’échelle humaine peut dégager une quantité considérable d’énergie, par exemple, un gramme de matière que l’on annihilerait par collision avec de l’antimatière correspond à environ 10^{14} joules, soit approximativement l’énergie dégagée par les premières bombes nucléaires.
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E=mc2 (song) — Wikipedia
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E=mc2 — Wikipedia
この項目では、質量とエネルギーの等価性を表す関係式について説明しています。その他の用法については「E=mc2 (曖昧さ回避)」をご覧ください。 
この記事には参考文献や外部リンクの一覧が含まれていますが、脚注による参照が不十分であるため、情報源が依然不明確です。適切な位置に脚注を追加して、記事の信頼性向上にご協力ください。（2016年11月） 
E = mc^{2}（イー・イコール・エム・シーじじょう、英: E equals m c squared）とは、
の物理学的関係式を指し、「質量とエネルギーの等価性」とその定量的関係を表している。アルベルト・アインシュタインにより、特殊相対性理論の帰結として、1905年
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E=mc2 (disambiguation) — Wikipedia
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What is the significance of E = mc2? And what does it mean?
Ronald C. Lasky, director of the Cook Engineering Design Center at Dartmouth College, explains the significance behind this hallowed equation:
It is the most famous equation in the world. Many can recite it—and attribute it to Albert Einstein—but few know its significance.
It tells us that mass and energy are related, and, in those rare instances where mass is converted totally into energy, how much energy that will be. The elegance with which it ties together three disparate parts of nature—energy, the speed of light and mass—is profound.
Here is where the equation of all equations comes from:
It was known for some time before Einstein’s insights that electromagnetic radiation (light, for example) possessed momentum. This quality of radiation is small in magnitude—after all, you needn’t worry about being knocked over by sunlight—but easily measurable. Applying an understanding of light’s momentum within a little thought experiment, it is possible to see how E = mc^{2} comes about.
Consider a cubic hollow box at rest in space with sides of length D and a mass of M. This box is also symmetrical in its mass distribution. One of the faces inside the box is coated with a fluorescing material, and, at a given moment, a photon (i.e., a particle of light) is emitted from that material, perpendicular to its surface. The momentum of this photon causes the box to move in the opposite direction as the photon, and it continues to move until the photon hits the opposite wall. During this time the box moves a very small distance, Δx.
Image: RONALD LASKY 
Newton’s laws of mechanics tell us that the center of mass cannot move, because the box has not been acted upon by an outside force. However, in order to keep the center of mass constant, since the box has moved, some mass must have been transferred from the fluorescing side of the box to the absorbing side in the process of generating the photon and its striking the opposite side. Therefore the photon must have a mass, m.
So the photon, which also possesses energy E, is emitted from the fluorescing side of the box. Its momentum, P_{photon}, is equal to its energy divided by the speed of light: P_{photon} = E / c. The photon will impart this momentum to the box, causing the box to move a small distance, Δx, during the time, t, in which the photon travels to the opposite side of the box. The momentum of the box, P_{box}, is also equal to its mass, M, times the velocity, v_{box}, at which it moves before the photon strikes its target. (Note: The box loses the photon’s mass, m, during this process, but this slight loss can be neglected here.) Hence:
P_{photon} = P_{box} = E / c = Mv_{box}
Then v_{box} = E / cM(1)
We can also determine the time it takes for the photon to travel across the box: it is equal to the length, between parallel faces, of the box (which is D), minus the amount the box moved in the opposite direction (Δx), divided by the speed of light, c. (The target will essentially have moved a slight distance closer, meaning the photon did not have to travel the full distance D.):
t = (D — Δx) / c
But, since Δx is a minute fraction of D, we essentially get:
t = D / c (2)
Now, since v_{box} = Δx / t , using equation 2, v_{box} can be restated as:
v_{box} = Δxc / D(3)
Substituting equation 3 for the term v_{box} in equation 1:
Δxc / D = E / cM
Next, we rearrange the terms to get:
ΔxM = ED / c^{2} (4)
Assuming the center of the box is initially at x = 0, this position is also the center of mass, x_{m}. After the photon event, the box moves Δx to the left, as shown in the figure below, and the equivalent mass of the photon, m, is deposited on the opposite side. As mentioned above, we recall from Newton’s Laws that the center of mass must not change, because the box is not acted upon by an outside force. This concept is expressed in the center of mass equation below. The center of mass is at x = 0 in the left half of the equation and it is still at 0 after the photon strikes the opposite wall as described in the right half of the equation.
x_{m, initial} = x_{m, final}
0 = (–MΔx — mΔx + mD) / M
Grouping like terms:
0 = (mD — (M + m)Δx) / M
Solving for Δx:
Δx = mD / (M + m)
Since m is extremely small:
Δx = mD / M (5)
Substituting equation 5 into equation 4:
(mDM) / M = ED / c^{2}
The mass of the box and D cancel out, leaving:
m = E / c^{2}
Which rearranges to:
E = mc^{2}
www.scientificamerican.com
E=mc squared
Mass To Energy Calculator For an energy to mass calculator in which m = E ÷ c², click here
You may have wondered what this mysterious equation is all about. It seems that knowing Basically, the equation states that matter and energy are identical.
The mass (from the above example) would be 3 kilograms and the speed of It is fascinating and quite intimidating to learn that a matter to energy conversion of just one gram yields the equivalent of 21.5 kilotons of tnt — the energy of the Hiroshima atomic bomb. Yes, all that power is generated from one gram of matter transmuted into energy — the mass of one paper clip! The calculator below is very easy to use. Input a number, click on the units this Numbers are displayed in scientific notation in the amount of Return To Home Page Copyright © 1999 — 1728 Software Systems 
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E=mc2 lyrics — Big Audio Dynamite original song
Somebody I never met
But in a way I know
Didn’t think that you could get
So much from a picture show
Man dies first reel
People ask what’s the deal?
This ain’t how it’s supposed to be
Don’t like no aborigine
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Took a trip in Powis Square
Pop star dyed his hair
No fans to scream and shout
When mobsters came to flush him out
Gangland slaying underground
New identity must be found
On the left bank for a while
Insanity Bohemian style
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Met a dwarf that was no good
Dressed like little Red Riding Hood
Bad habit taking life
Calling card a six inch knife
Ran off really fast
Mumbled something ’bout the past
Best s** I’ve ever seen
As if each moment was the last
Drops of blood colour slide
Funeral for his bride
But it’s him who’s really dead
Gets to take the funeral ride
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Space guy fell from the sky
Scratched my head and wondered why
Time slide into time
Across international dateline
Scientist eats bubblegum
Hall of fame baseball
Senators a Hoodlum
Big chiefs in the hall
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Stray thoughts fear to tread
Placed upon the screen instead
Shes my flame too hot to hold
Had to settle for her cold
Bloodlust — Greek God — Gold discovery
Gone bust — Tight wad — Slow recovery
Axe job — Flame thrower — Ironbar and gun
Betting shop — New owner — A walk in the sun
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Spread the news the Maestros back
With a beat — box soundtrack
The King of brains — Queen of the sack’
Executives have heart attack
It’s assault course celluloid
The money makers would avoid
Sometimes notions get reversed
Centre of the universe
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
Ritual ideas relativety
Only buildings no people prophecy
Timeslide place to hide nudge reality
Foresight minds wide magic imagery
www.lyricsfreak.com
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