Talk-Polywell.org

Um, by definition P = Fr*vr + Fu*vu. If you disagree with this, then I don't know how else to explain it. Go sit down and derive total rate of change of kinetic energy. If I substitute in Fu = -Fr, then I get P = Fr*vr - Fr*vu = Fr*(vr - vu). Where is the problem. What does kcd think those equation...

I don't understand what you mean "F*(vr-vu) doesn't work". That is by definition the total rate of change of kinetic energy. Maybe you are confused because Fu is negative: F = Fr = -Fu.[/quote]
Exactly: F*vu cannot be negative, if it is defining a KE increase.

Of course this would imply that the faster you go, the more energy, you would need. Absolutely. This is what the maths clearly says. And, of course, if one were barrelling along under the high seas at speed, then forcibly slowing oneself down against the sea would dissipate power rather than consum...

I prefer the analogy of a submarine and its propeller. Better still, indeed! So, now contemplate if some race of beings lived in what appears to be a sealed capsule bobbing around within a medium, and one of them created a gadget that he claimed could thrust against the surrounding medium. Discount...

Which means the power I see is Pk = F*v = F*vr*(1 + Mr/Mu) And the total real power consumed by the rocket (what the pilot reads from the engine) is P0 = F*(vr - vu) = F*vr*(1 + Mr/Mu) So indeed Pk = P0. No problem there. It is possible kcdodd will need to reconsider this maths... It is saying that...

Hmm, not sure how that affects the thinking process, but I have been wondering whether it is better to imagine a swimmer diving under water, pushing himself forward with his hands. In a sense the entire pool is his reactionmass (though in this case the nearby water molecules are receive the most ac...

GIT has a capacity for reasoning that is unchallengeable.

OK, so he has no reasoning capability, but nonetheless it is unchallengeable!!

Does the universe have a momentum in a certain direction? No. However, mass in the universe does have a momentum - it's expanding outwards because some expansionary force is stronger than gravity. This makes little sense. Either it has a momentum in a direction (which may be a zero momentum) but if...

Does the universe have a rotational angular momentum? No (at least assuming Mach's Principle is true). The rotation thing introduces a whole new dimension. The analogy of a car on the surface of the earth was not intended to suggest rotation was the end result. However, the analogy is significant i...

I think this is probably the chapter that GIT is talking about, it's about Mach's Principle in a book edited by Barbour and Pfister: This awful link will shoot pages worth off the side of a typical screen. Try editing the post, using the following link instead; http://books.google.ca/books?id=fKgQ9...

Where, in this thread, is there a criticism of a theory!?!?

GIT keeps saying it, and, one must presume, in his idea of 'reasoned arguing' (a pretty bizarre place to be, it seems!!), if he says it often enough it becomes true!

So there is no doubt that in GIT's touch-feely 'analysis-without-analytics', he consigns conservation of momentum to the dustbin on the strength of a few equations that he doesn't understand himself, and that few accept and that have yet to be demonstrated to have any practical value? ..compared wit...

You're jibbering word-salad, chris. When you write "so how can it react against something else that is not in a defined frame of reference?" you are not even wrong. Is there anyone else in this forum that can explain, in a more readily intelligible way, what GIT's complaint with chrismb's post is? ...

You don't understand Mach's Principle. .... You can't have sensible discussions of things like conservation when you still have no working knowledge of the theory you're criticizing. There is no criticism of any theory in this thread. There is only the deductive conclusions arising from an initial ...

First, no thruster can change the total momentum and energy of the universe from an inertial reference frame, right? From a conceptual point of view, that would seem true. From a purely Newtonian perspective in which the Universe has 'an inertia', where some of which can transfer to a remote object...