Why is must E=mc2?

Question

I always wonder why must E=mc2. Since scince need very accurate farmular, this formular seems a little bit too ideal. Why not E=mc3 or E=mc0.13157668464164984651684984654684...... something. If Energy really = mass * speed of light square, pleeeeeeeeeeeeeease tell me how Einstain's bloody hell intelligents prove it.

Answer 1

Well, there is an agreement of measurement units:
E=energy ... unit (SI)=joule=kilogram X (meter /second^2) X meter =newton X meter
m=mass ... unit (SI)=kilogram
c=speed ... unit (SI)=meter/second, c^2=speed^2=meter^2/second^2
The thing that c is the speed of light and not another speed has to do with the type of energy described by this equation, and the experimental proof of the nature of this energy (including the use of approximation-rounding up during experiments) is a different matter.

Answer 2

The famous equation was an extension of work done previously by many physicists.
It was known that, according to Newtonian Mechanics, that the total kinetic energy of an object was represented by the formula: E=1/2MV^2.
As you can see, if the velocity is zero, the energy of the mass is also zero.

Rest mass is often noted as Mo, and up until relativity stepped in, the energy content of this "rest mass" was zero.

Einstein's work resulted in the discovery that the actual kinetic energy formula was E=mc^2/sq.rt.(1-(v^2/c^2) and from this came E=sq.rt.m^2c^4+p^2C^2, where P equals relativistic momentum. In this "simplified (!)" formula, when V=0, then P=0 and the formula reduces to E=MoC^2, or the notorious E=MC2.

Even Einstein struggled with this concept, wondering if it was just a mathematical fluke - fortunately, he had the genius to determine that it was indeed the way the universe actually operates. And, over a hundred years later, the formula is still pretty awe inspiring!

Answer 3

Einstein did derive E = mc^2 from earlier works and experimental results. So it is not an approximation or a WAG. Actually, one of several derivations, based on the conservation of momentum, is rather straightforward and requires no extraordinary math beyond undergrad physics and trigonometry. [See source.]

But what is more to the point, E = mc^2 has been proved over and over again in the lab, industry, and the military. We use E = mc^2 as a fundamental basis for designing and operating nuclear power plants for example. At this point in time, E = mc^2 has stood the test of time and countless experiments.

Answer 4

It's proven by every nuclear detonation that has ever occurred. The measured energy output from such detonations, given the mass of the input materials, exactly matches Einstein's famous formula. It was his formula that allowed such devices to be developed in the first place.

That the formula includes the term of the speed of light squared tells us a lot about how the atomic structure of mass and the laws of electromagnetic radiation are related...but it seems so "tidy" mainly because of the units chosen to represent energy, mass, and the speed of light. If you used miles per hour for the speed of light rather than kilometers per second, the formula looks a lot more messy :) That the metric units of measure for these items were all derived from natural phenomena is what gives the equation it's "tidy" appearance.

Answer 5

In classical mechanics, momentum and energy are properties which can be proved to be conserved for a set of freely moving point particles traveling in different directions by assuming that the laws of physics do not depend on where you are, how fast your reference frame is moving, and what time it is, assuming a Galilean transformation from one reference frame to another. This is where you simply add the frame velocity vector to all the particles' velocities.

Dr. E replaced the Galilean transformation with the Lorentz transformation, whose basic assumption is that the speed of light is the same in all reference frames. He then mathematically determined how the definitions of momentum and energy must be modified in order for them to be conserved, again assuming position, velocity, and time invariance, but this time given a Lorentz transformation between frames. He discovered that, in order for energy to be conserved, one must add mc^2 to the definition of energy. I can imagine him spending many sleepless nights trying to get rid of this embarrassing addition to the concept of energy before finally conceding it.

Answer 6

well, if you were going to write energy in terms of mass and the speed of light, then, up to a constant, E would have to be mc^2 to make the units work out right. For example, the expressions mc^3, or mc are not units of energy.

Answer 7

Why do you dislike simple formulas?

They are ALWAYS preferred over complex ones since they hide nearly nothing inside long involved math expressions.

Einstein's intelligence proves nothing. His formula has been verified for over 100 years and never found to be at fault. I'm putting my money on HIM, not YOU.

Answer 8

You have to go through the whole theory and all the explanations. Don't expect us to give you a full proof and detailed explanation. Look at sites related to Einstein and his theories:
http://www.worsleyschool.net/science/files/emc2/emc2.html
http://en.wikipedia.org/wiki/E%3Dmc%C2%B2
http://www.aip.org/history/einstein/emc1.htm

Answer 9

cause when atom of the light reflact to the surface that time surface it slef recduce energy so here eqaution like this coming light of atom x reduce atom of light = velocity of light ^2 (c^2)

Answer 10

there is a very simple answer to this unecessarily complex question of yours(now now no offence!)....

look,,we dont --we always multiply things like this: f*f*f*f or c*c
so did einstein......he did c*c=c^2...it is according n based on many other formulas from where it has been taken,...