What does e in e MC squared?

Answer 1

The formula E=mc2 shows that matter and energy are interrelated, matter can be converted into energy and energy can be converted into mass. E=mc2 Where: E is Energy in Joules (J)

m is mass in kilograms (kg)

c is the speed of light in meters per second (ms-1) which is 3.0x108 ms-1

c2 = 3.0x108 x 3.0x108 = 9.0x1016 The simplest way to show how to use the formula is to give some examples. Example 1 - Burning Coal

If we burn 1 tonne of coal then about 36GJ of energy is released.

Rearranging the equation E=mc2 we get m=E/c2

so m = 3.6x107/9x1016 = 4x10-10kg = 0.4μg If we weigh the coal and air before burning and the ash and air after burning we would find that the stuff remaining afterwards would be 0.4μg lighter than what we started with. Obviously it would be impossible to measure a change of 0.4μg in 1 tonne of coal and about 10 tonnes of air but with more energetic reactions and very sensitive equipment it has been shown to be true for chemical reactions. Example 2 - Fission of Uranium-238

The results are more useful in nuclear reactions, during the fission of 1kg of Uranium-235 about 6.7x1010J of energy is released. Using the equation m=E/c2 as we did in example 1 we get m=6.7x1010/9x1016 = 7.4x10-7kg = 0.74mg. A loss of mass of about 0.000074%, small but definitely measurable. Example 3 - Total conversion of matter

If we were able to convert 1kg of mass completely into energy (the only way currently known how to do this is to have antimatter to collide with matter but the amounts produced with our current technology have not exceeded a couple hundred of atoms) then the energy released can be calculated using E=mc2.

E = 1 x 9x1016 = 9x1016J. Example 4 - Providing all human energy requirement using matter conversion

Finally, in 2005 the Earth's total energy use was 5x1020J. If it were possible to convert matter fully into energy then we can calculate how much mass would be required. m=E/c2 so m=5x1020/9x1016 = 5500kg. The total annual energy requirement of human kind could be provided from just 5.5 tonnes of matter. Its a pity it can't be done........ Notes on limitations of data used above * The figure of 6.7x1010J/kg for Uranium-238 is not very accurate, I estimated it from data in the Encarta link below, it is good enough for an illustration here but I would not suggest using it elsewhere. * See reservations in Wikipedia source link about total energy use of human kind.

Answer 2

Two ways:

1) If you start with Einstein postulates, then you can derive the above formula. You will need some calculus, but it's pretty straitforward.

2) Perform an experiment involving nuclear reactions. Measure the mass at the start of the reaction, the mass at the end of the reaction, and the total kinetic energy of the end products. You will find that the kinetic energy is exactly equal to the "lost" mass, when multiplied by c^2 .

Answer 3

E=mc2 is an algebraic term famous by Albert Einstein, its questions if its mathematical, or scientific. is between is mathematical but its for scientific reasons.

Answer 4

Hahaha! I got you good!! :D :D :D :D :D

Answer 5

yes.