# Can you explain the equation/formula E=MC2?

Is it the formula for relativity?

### 11 Answers

- 1 decade agoFavorite Answer
The equation E=MC2 is the derivation from Einstein's relativity theory. this is not a case of the classic mechanics. this equation explains the value of energy of an atom.

E-> Energy

M-> mass of the atom

C-> speed of the light.

in this only speed of the light is constant. the mass differs by frame to frame in accordance to theory of relativity. so the energy of the atoms also differs with frame to frame. but this equation is not fully correct and Lorentz had made corrections to it.

Anybody who can prove this equation as a total wrong thing with strong evidences will be announced as the greatest of the universe..

- 1 decade ago
First, a little bit about Einstein’s Special Theory of Relativity. It started with two postulates: 1) that the laws of physics are observed to be the same as long as you aren’t accelerating (i.e., you’re moving at a constant velocity) and 2) that the speed of light c is observed to be the same for all observers.

In special relativity, one is always comparing what happens in two (or more) “reference frames,” moving at some constant relative velocity to one another. Shortly after he published the special theory in 1905, Einstein published a second paper about a particular result. Basically, he imagined what would happen if you had an object with a certain mass emitting light—then you observe that object from a frame of reference in which it’s at rest and a frame of reference in which it’s moving with some constant velocity. He found that the energy carried by the emitted light is different in those two cases. But the total energy has to be conserved (i.e., it has to stay the same in both frames of reference). Where does the additional energy come from? From the kinetic energy of the object.

Kinetic energy is simply energy of motion: it's proportional to the mass of the object and the square of its velocity. But we know how fast the object is going in both reference frames because that’s built into the problem. So the energy must result in a change in the mass of the object! Some tiny mass m is given up to provide the additional energy; it turns out that it does so proportional to the speed of light squared.

Thus, you end up with the formula E=mc^2, which results from comparing the same physics problem from two different perspectives in special relativity. It turns out that this has great implications for quantum mechanics (the study of nuclear energy, for example), but it originated from relativity.

Ryan Wyatt

Rose Center for Earth & Space

New York, New York

Source(s): Someone already pointed out the original paper online: http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ - 1 decade ago
Energy equals mass times the velocity of light (c) squared. It's not the formula for relativity as such (which is a tad more complicated) but explains that mass/matter can be converted into energy and gives the formula to calculate how much energy matter contains. This is important because in nuclear reactions, a small percentage of the mass of radioactive matter is converted to energy, an enormous amount of energy in fact. The fact that so much energy is stored in matter is what gives the atomic bomb its incredible power.

- xaviar_onasisLv 51 decade ago
No, it isn't the formula for relativity. What it is is a way to express how mass and energy are related.

Since the term C^2 is a constant, the equation shows that as the amount of energy increases, so too does the amount of mass. One offshoot of this is that something traveling faster (more energy) will weigh more (more mass) than it would if it weren't traveling as fast.

Relativity is about how you would go about measuring 'faster' in the previous statement. 'Faster' is related to how someone else doing the measuring is moving.

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- Anonymous1 decade ago
The formula gives a mass energy equivalence relation.It gives an idea of how much energy can be obtained by converting a small amount of mass.Basically mass is concentrated energy.In the eqn E represents energy , m mass and c the velocity of light.

- PearlsawmeLv 71 decade ago
If any object moves with certain speed its mass increases.

This concept was unknown to classical physics.

The increase in mass is very small when the speed is NOT comparable to the speed of light.

When the speed approaches the speed of light the increase in mass is tremendous.

The mass becomes infinite when it speed is equal to the speed of light.

Thus we have a NEW type of energy called “ENERGY OF THE BODY” due its mass.

Every object has some “energy of body” called its REST MASS ENERGY when the speed is zero.

This ‘energy of body’ is calculated by a very simple formula. E = M0. C.C.

M0 is the mass when the velocity of the body is zero. C is a constant = 3x 10^ 8 m/s^2.

If the body attains a velocity v, its mass increases to M. (There is a formula to calculate the mass of a body when it moves with a velocity v)

The ‘energy of body’ is now M. C.C.

The difference between the two states of energies of body is the kinetic energy of the body. In classical physics it was equal to ½ m .v.v.

But now we see that it equal to M. C.C - M0. C.C. = (M - M0). C.C.

If (M - M0) = m, Then we get kinetic energy of motion is m. C.C

Note that all formula has the same form mass x a constant x constant.

But the mass involved is different in different equation.

In the case of light it s energy is given by h n (n is the frequency)

This is completely kinetic energy; not energy of body.

If we equate it to mcc, then we get m = h n/ cc.

The mass equivalent of photon is h n/ cc.

The rest mass of the photon is zero.

When a photon moves with velocity C, its kinetic energy is h n

The Energy of body is zero. But its K.E is equivalent to a mass (h n/ cc)

- SteveLv 71 decade ago
One of several formulas from the thoughts of Albert Einstein in his 'miraculous year' (1905) that relates the mass and energy content of all matter. For the derivation of it in his own words and formulas, see

http://www.fourmilab.ch/etexts/einstein/E_mc2/www/

Especially read the explanation in yellow at the bottom of the page. Einstein used the letter L for energy and never actually WROTE E = mc^2, but rather used the WORD mass and L and c (still used for the speed of light) to get his idea across.

- 1 decade ago
it is simple. the formula means energy is equal to mass times the speed of light squared. this is the formula for e=mc2

- 1 decade ago
According to Albert Einstein, Energy(E) released by an Object can be obtained by multiplying the object's Mass(m) with the square of the speed of light(c^2)

Thus, E = mc^2 was born.

where:

E = Energy released by an object

m = mass of the object

c = speed of light

- 1 decade ago
When an atom is destroyed, the energy given off is calculated using the formula:

e=mc^2

where

e=energy in joules

m=mass in kilograms

c=speed of light in meters/second