botach wrote:
dcbwhaley wrote:
This argument is now about semantics rather than Physics so I shall...
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Thanks ,gents , before the GOOD name of SS gets besmirched .Thats what I suggrested several posts previous .
So SHAKE HANDS & call it a draw .
Nope. The questions have not been answered; all the subsequent ones have been ignored.
dcbwhaley wrote:
It's a draw.
Who are you trying to kid? You weren't even close!
You evaded one of the critical questions and skirted around another. For the third/forth you repeated your thought experiment which I had already shot down, and shot down again with the very damning:
Steve wrote:
Consider the following thought experiment. A small self-powered (battery, ICE) moving vehicle uses a normal friction brake to dissipate the kinetic energy via (at least partly) thermal radiation (just like our original example). If “conveniently” choosing the system to be the planet and the vehicle, momentum is conserved but energy is varied.
Thus I can now make the bold statement, relating to your original example, that “momentum is always conserved; energy isn’t.”, yes or no?
That's a tricky one for you, huh DCB !
Even your "convenience" won't get you out of this one! But I guess it is more convenient for you to just ignore it altogether, right?
Let me prove how it applies to your original claim:
dcbwhaley originally wrote:
And controlled stopping of a car is involves converting that kinetic energy into heat.
So where did that heat go? That "heat" has a component in the form of thermal radiation, which immediately leaves your "system" as you had defined it. Thus, by your own definition, energy wasn't conserved. You were wrong from the start!
So as you can see, whatever answer you gave for the "description of the circumstances where momentum isn't conserved whilst energy is?" has disappeared in a puff of logic. And that was with my first thought experiment I posed to you - and it was based wholly on your example.
In any correctly closed system, energy and momentum always remain constant. The definition I gave proved that your portrayed interpretation is wrong.
Given that you suddenly gave up, and that you misrepresented, lied and were hypocritical, its a bit difficult to conclude you aren't trolling.