Enstien theory of relativity...?

Question

Can please someone tell me the answer to this question:

Regarding the theory of relativity developed by Einstein in 1905, which one of th e following statements is not true?

A. Einstein assumed that light always travels at a constant speed in vacuum of 299,792,458 or 3*108 m/s.

B. The relative mass m is always larger than the rest mass mo of any particle.

C. No particle or object can travel at a speed equal or greater than that of light.
D Energy released in a chemical explosion is proportional to the difference between the mass of all reactants and the mass of all
products.

E. The gain in kinetic energy by a particle can be achieved by losing its mass.

Answer 1

Statement A is true. But it is not the theory of relativity.

Even before the theory of relativity it was known that the speed of light in vacuum is constant and equal to 3*10^ m/s.
Even before the theory of relativity it was also known that the speed of light in vacuum is independent of the source of the light. That is to say, light once emitted from a source will have its own speed.

But what was new is that there is no relative speed for different observers moving with different speeds.

All will measure the speed as C and this is true even when one moves with the speed of light in either direction.
That is speed of light is not relative to the observer. {For example speed of sound will differ with the speed of wind and the speed of observer etc.)

The speed of light is absolute.
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Statement B and C are correct or true.
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Statement D is not clear.
There is a mass difference before and after explosion. The difference in mass is converted into energy.

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Statement E is wrong. The kinetic energy of a particle is due to the increase in mass of the particle and is the direct consequence of statement B which is true.

The classical formula 1/2 m v^2 is no more valid for speeds comparable to that of speed of light.
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Answer 2

There are problems with at least THREE of these statements. However, part E) is DEFINITELY UNTRUE.

A) While Einstein assumed that light travels at a finite and constant speed c in a vacuum, he didn't assign any particular value to c, understanding that its value is subject to experimental verification. It was in fact known at the time both more accurately than 3 x 10^8m/s, but far less well than to 9 significant figures! So, because of the specificity of part A), it is in fact NOT TRUE.

C) should say "... at a speed equal or greater than that of light IN A VACUUM." (When particles travel at speeds greater than that of light in some given MEDIUM, "shock waves" of light called Cerenkov radiation are emitted. They are the analogue of sonic booms in air.)

E) is simply gobbledygook, and does not make sense as it stands. In fact as Einstein showed, the "effective mass" for a moving particle of rest mass mo (in a given rest frame) is
m_eff = mo / [sqrt (1 - v^2 / c^2)]. The energy equivalent of this, m_eff c^2, is LARGER than mo c^2 by an amount which reduces to the classical kinetic energy, 1/2 m0 v^2, at low speeds (low in comparison to c). Athigher speeds its mathematical form naturally changes. The difference between m_eff c^2 and mo c^2 can be thought of as providing a quantity we can define as "kinetic energy" at all speeds. However, that doesn't really help serve any other purpose. Physicists applying relativistic concepts to analyse the results of high energy experiments tend to use the total energy in their analyses, rather than "splitting off" the two separate parts. (There are however some "threshold" considerations where one could argue that it still plays a useful role.)

In any case, the "gain in internal energy" is part of the increased effective mass of the particle due to it being in motion. It does NOT come at the expense of the particle LOSING its mass or mass-energy, but rather as a result of the latter being INCREASED by whatever accelerative forces are acting on it.

So part E) is the answer that is DEFINITELY WRONG, while other parts are only perhaps rather flawed statements that can be expressed more accurately.

Incidentally, despite what some responders have said, part D) is certainly TRUE. The energy of chemical explosions or indeed the non-explosive heat generated in some chemical experiments comes from a change in the binding energy of electron clouds in the atoms and/or molecules involved. These effects are analogous to the changes in nuclear binding energies involved in nuclear explosions. Both are subject to Einstein's celebrated relation

ΔE = Δm c^2.

The great, indeed dramatic difference in their effects is attributable to the fact that the binding energies of the electrons in atoms and molecules are of order eV, whereas those of the nucleons are of order MeV, a million times greater!

Live long and prosper.

Answer 3

C is false.

Einstein said nothing can go faster then light in a vacuum. That vacuum part is important.

Have you ever seem the blue light in a nuclear reactor? That light is caused by elektrons (Beta-radiation) which are moving faster then the light does in that water.

Answer 4

evaluate the time it takes to combine the factors and bake the truffles. The time varies with what proportion bran truffles you ought to make, besides through fact the dimensions of the truffles. That reported, bran truffles will advance in mass as they recommendations-set easy velocity and contract quite than strengthen. See my previous remark on the sci notation of the bran muffin. .

Answer 5

My vote is "E"

KE = 1/2 mVsquared. so if you lose mass, KE goes down, not up.

The only one I can't understand is B... so lets just wait to see what some others say.

Answer 6

It is difficult to say what Einstein said verbatum.

Answer 7

(d), it's nuclear explosion, not chemical explosion.

(a), (b) and (c) are definitely true.

(e) is also true because mass and energy are interchangeable.

Answer 8

c, I think. That is proved with e=mc^2.