Physics question on Einstein's postulate?

Question

I cant really get the right answer for this question!

can someone plz answer this??

here is my question

Explain how the equation E=mc^2 is consistent with the Law of Conservation of Energy.

thx

Answer 1

Postualtes:

The laws of physical phenomena are the same in all inertial references frames (that is, only the relative motion of inertial reference frames can be measured; the concept of motion relative to “absolute rest” is meaningless).

II. The velocity of light (in free space) is a universal constant, independent of any relative motion of the source and the observer.

Based on these postulates ,

If one meter rod is moving with half the speed of light, we will say that its length has contracted to 0.86 m

When a clock moving along with the rod records 1 second elapsed, as seen by the man in the rod, we will say 1.155 seconds has elapsed in our clock.

If the mass of the meter rod is 1kg when it was not moving, we will say that its mass is 1.16 kg when it moves with half the speed of light.

Mass of a moving object is not a constant or absolute and it is relative. depending upon the speed. The kinetic energy of a moving body is proportional to the increase in its mass which is due its speed.

There is no absolute mass. But there is rest mass, i.e.mass when its speed is zero, Thus there is relative mass alone.

The energy that we gave to an object to aquire a speed is manifested in the form of its increase in mass.

It seems now that conservation of mass is violated. But if we realise that mass is relative, we can see that it is not violated.

Thus increase in mass is the measure of its energy.

Hence the two conservation laws are related by the simple equation
E = [m - mo] c^2 where E is the increase in kinetic energy and [m - mo] is the increase in mass.

When the object is at rest it has no kinetic energy. It follows that moc^2 is a form of initial energy or rest mass is equivalent to an energy of moc^2.
As long as ojects are not in motion law of conservation of mass is valid.
Once they are in motion we have to apply this law taking into account the increase in mass due to relativity.

Answer 2

Well, it was derived from the law of conservation of energy. Einstein got this by analyzing an electromagnetic wave in a resonant cavity. What this relationship says is that mass and energy are interchangeable. You can convert mass to energy or vice versa. A good example is the creation of two photons (energy) by the annihilation of an electron with its anti-particle, the positron. The inverse process creates the electron-positron pair.

So energy is conserved - it just gets converted to mass.

Answer 3

Jose is authentic, yet (d) is the main maximum suitable suited answer of the techniques. Einstein did assume (d) and further to it the concept that the fee of light is the comparable of all observers. In a fashion, however, the fidelity of the fee of light must be considered a organic extension of postulate (d) in case you comprise Maxwell's equations in "regulations of physics". Maxwell's equations say that the fee of light is continuous. So in the event that they notice the two nicely to any inertial observer (and not in some particular physique of reference--the ether--as grew to become into theory), then the fee of light might desire to be consistent to any observer. All this confirms that any instructor who supplies distinctive decision (and semi-ambiguous) distinctive decision questions is the two lazy or stupid.

Answer 4

Energy is neither destroyed nor created, it is simply transformed from one type to another. Well, now mass is included in as a "form" of matter.

Answer 5

Energy and mass are just different forms of the same thing. No energy or mass is lost, just transformed.