why did Einstein use the E = MC Squared Equation?

Question

why the speed of light squared...why not just Speed..if i tap a nail with a hammer theres not much energy but if i haul back and slam the nail theres more energy and my arm wasn't going the speed of light squared...or does his equation have to do with nuclear energy?

Answer 1

The 'experiment' you describe to illustrate your question indicates a misunderstanding of the 'narrowness' of Einstein's theory. You are referring to total energy, which includes such things as kinetic and potential energy.

Einstein's theory refers to objects at rest (i.e. not in motion); which is why the 'E' is more properly described by physicists as Eo (Energy at rest).

Eo = MC2

The theory reveals to us that Mass is only a form of Energy and that all objects with mass have energy - even when they are at rest.

C squared (twice the speed of light) is the constant factor used to convert units of energy and units of mass.

This energy at rest can be transformed to many other forms of energy such as kinetic, luminous, calorific, etc. (e.g. your 'experiment') but this is not part of that specific formula.

The formula is telling us that mass is just concentrated energy. If we wish to know how much energy a system has at rest, we simply measure its mass.

The advent of nuclear reactors and bombs was the first occasion at which Einstein's theory could be proven. It turned out to be extremely accurate.

Answer 2

Yes it's nuclear. It's the algebraic equation that shows the relationship between energy and matter. When atoms are either fused or dissolved, they release energy. The sun and all other stars do this constantly. Matter x the speed of light squared is the speed at which nuclear energy is released. This mathematic principle had to be understood before a man-made nuclear explosion could be produced.

Answer 3

The equation is derived by applying the transformation equations of special relativity to physical situations in which enegy and momentum are conserved. In order to reconcile the mass/velocity transformation with energy conservation, the total energy of a moving body with velocity v and (rest) mass m is found to be:

E = mc^2 + .5mv^2

The classical formula is E = .5mv^2.

What the formula showed that even when the object is at rest (v=0) it still has energy, leading to the conclusion that the mass itself represents energy.

This derivation has nothing to do with nuclear energy.

The idea that the mass could be converted into energy did not exist at the time and came much later when it was noticed in fission reactions that the combined mass of atomic particles preceding the reaction was more than after the reaction, and that the mass difference represented the energy released. That mass difference is entirely due to the different binding energy in the nucleus, since no physical particles are destroyed to create the energy.

The opposite, converting energy into mass was understood to take place when an object is accelerated to a velocity. According to the transformations of special relativiy, the mass of that object increases as the velocity increases. This can be interpreted as some of the energy trying to accelerate the object going into increasing its mass rather than increasing its velocity. You "push" more and more, but the velocity increase diminishes the faster it goes. It takes an infinite amount of energy for the object to reach the speed of light.

Answer 4

Why does everyone have a need to phrase what E = mc^2 means?

E = energy (in joules)
m = mass (in grams)
c = speed of light (m/s)

Very similar to Kenergy Ke = (mv^2)/2

E = mc^2 shows how much energy is in any amount of mass. Hence, it also tells us that driving 16miles per gallon of gasoline is hugely inefficient.
In reality, one drop of gasoline (a little less than one gram since it's lighter than water), has enough energy to last over a billion miles in any car. After all, the speed of light squared creates a gargantuan number of joules. But nothing is that efficient. The only thing that comes close are nuclear reactions. That's why they use that equation in nuclear physics.

You can even figure out that if your body was super efficient at eating food, you'd only need like one cookie for a whole year. If it was super efficient, you wouldn't poop either because all energy of a cookie would be used.

Answer 5

HOW he actually came to that simplified equation is enough to fill several chalk boards, I'm sure...

E=MC^2 applies only to thermonuclear reactions IN a perfect world... that is, Energy equals Mass x C squared, if you have a perfect, flawless conversion of mass to energy with no waste and no byproducts. Striking the nail with the hammer just doesn't fit the bill ;-)

Hope this helps.

-Daniel

Answer 6

Somebody said it right: The e=mc^2 result came from other parts of other equations. And yes, it is if you could release ALL the energy of the mass involved. Stars can't even do that...it would take matter/anti-matter contact to totally anihilate the matter into energy. If that could be acheived, well...the energy released from a single sheet of paper would be the size of a large power plant exploding.

Another result Einstein deduced, and tried to correct for because he could not beleive it, was that the universe has to be expanding. he added a fudge factor to fix it, then later called it the biggest mistake of his career.

Answer 7

Yes, it is the nuclear energy.

The energy of motion (of Newtonian physics) uses the square of the velocity of the object. But in the case of nuclear energy, the object may be at rest, so then its kinetic energy is zero, but it still packs a mighty puch in terms of nuclear power. And that is a function of the speed of light.

Answer 8

For one thing, the dimensions would be wrong. But the real reason is that it simply dropped out of the other mathematics of the theory. Anything you can do will, however, have far too small a velocity to require the use of relativistic mechanics -- Newtonian mechanics will work just fine. The GPS spacecraft are moving fast enough, however, that a small relativistic correction is applied to their signals.

Answer 9

Because D was being used by the CD drive and A by the 3 1/2 inch floppy drive and B by the 5 1/4 inch floppy drive and C by the hard drive, The next logical choice was E.

Answer 10

Yes to nuclear energy! He used it because he was a genius.And because it was his theory! LOL