C Squared

I have been wanting to comment on 1/0 several times and thought better of it. So, you are being noticed-not to worry.

Hello Jim,

I found this from a physics book:
Newton's second law of motion F=ma is defined as F=dP/dt if the principle of relativity was used.

Then it goes on about the definition of work and energy, does a bit of calculus and comes up with this equation:

E= mc^2/sq.rt of 1-v^2/c^2

and then states the following:

"BUT THIS EXPRESSION IS NOT ZERO WHEN v=0; INSTEAD IT BECOMES EQUAL TO mc^2."

and then CHANGES THE EQUATION so that it is correct with the newtonian expression E= 1/2mv^2 where momentum is conserved.

Is something wrong here, or did this go right over my head?

Hi GD, I don't know what is the correct in your post. It seems to me both c^2 and v^2 are not real. They are abstract fabrications that work very well as long as limits are maintained. Velocity and acceleration are the real concepts and squaring velocity makes no sense except for the fact it works out mathematically. Do you happen to know when c^2 came into the mix? I suspect it was prior to 1900.

Jim,

I think c^2 did not come about until the end of the 19th century and is the result of Einstein's relativity principle.
(I did not find any other information stating otherwise.)

There are certainly others who contributed before him in this understanding, but "speed of light squared" is Einstein's legacy.

His equation E=mc^2 is still incomplete. His goal was to describe all physical phenomena - from the subatomic to the entire universe.

According to his theory of relativity, space would curve in the presence of a mass of energy (or matter), but there is no reference to space or time in his equation.

I think the reason for this is that space and time would then become "relative". This would be contrary to the law of conservation of momentum.

Which brings me to question these conservation laws.
I found this definition for conservation laws:
" Things that remain unchanged, in midst of change."
- What kind of B.S. is this ? -

Or this one:

"Conservation laws state that a particular measurable property of an isolated physical system does not change as the system evolves."

This contradicts a quote from a chemistry textbook:
"All systems strive to release energy. In other words, all chemical processes would prefer to undergo an exothermic process."
(notice the word "prefer" not to exclude conservation laws.)

And this one:

"Some conservation laws hold in many circumstances, but exceptions to them have been observed."

Is this a law or not ???

I think its time to do a clean-up in these definitions and equations!

GD, You are at the shore of the deep do-do so keep your rubber boots handy. This is where all the trails end in the muck. Anyway, back to c^2, you say it was not available prior to 1900? This detail is important to me and since it is the foundation of a lot of the theory postulated in the 20th century it seems a good idea to find out when and why it was first used. Don't get bogged down in the BS.

Hi Jim,

You can't disturb much if you are not at least knee deep in it. so only boots are out of the question. I guess a chest deep fly fishing pair of waders would be more appropriate.

C^2 can't really go far back: in Newton's time, electricity was more magic than physics.

The subject of electromagnetism came about in the mid 1800's.

Here is a link to a brief history or timeline on the subject of electricity (If electricity is not understood, c^2 won't either). It is just to show you that c^2 is a relatively new subject:


maxwell.byu.edu/~spencerr/phys442/node4.html

Apart from this, I do not have much else to add.