Recent content by Frank Peters

Is that correct? The nuclear fusion within the sun is caused by gravitational collapse. So it seems that, ultimately, it is gravity that powers everything.

Hydroelectric power, effected usually by damming a river, is ordinary considered an example of energy produced by gravitational potential. However, from an ultimate perspective, hydro power is actually an example of solar power. Water must drop to a lower gravitational potential to extract...

You seem to be saying two different things here. But mathematic does not admit infinite sums, or an actual infinite series. Such things are always defined in terms of a limit. However, post-Cantor, it seems that infinite sums are now realizable. We should be able to talk about a one-to-one...

Supposedly, infininity has been purged from mathematics. Both the infinitely small and the infinitely large have been replaced by the idea of a "limit." For example, a series x0+x1+x3+... is not considered to be a literal infinite sum with infinite terms but only the limiting value of an...

I did not realize that scrap recyclers performed elemental analysis on their product. I thought that they only separated ferrous from non-ferrous scrap and sent the all the ferrous material together to the mill as one big collection. So manual sorting of the ferrous material based on a...

?? Perhaps you misunderstand the issue. Steel is an alloy and the different types of steel contain different proportions of added metals such as manganese, molybdenum, vanadium, chromium, silicon, etc. Scrap steel must contain mixtures of different steel alloys and when this scrap steel is...

Radio waves are usually not viewed as streams of photons but according to quantum mechanics that is exactly what they are. But what does the wavefunction of an RF photon look like? If we consider a dipole radiator, say of 10 Mhz, that emits a single photon, my guess is that the wavefunction of...

Entropy is always increasing, say the thermodynamicists, and the increase will ultimately caue a "heat death" of the universe. But gravity seems to contradict this. Gravity, by clumping matter together, always engenders a decrease in entropy. Indeed, some cosmologists propose an eventual...

There are all sorts of things: covariant and contravariant vectors, metric components and the metric tensor, scale factors, differential quantities, transformations between different systems, etc., etc. In my experience, it is better to study these things using actual examples rather than the...

I am beginning to study the mathematics of curvilinear coordinates and all textbooks and web sites do not have realistic examples of non-othogonal systems. What are some examples of non-orthoganal curvilinear coordinates so that I can practice on actual systems rather than generalized examples...

An artillery shell is fired at, let's say, a 45 degree angle. The shell will rise to a maximun height and then fall back to earth, but the shell will also rotate considerably so that it strikes the ground with the nose forward. What accounts for the rotation? It would seem that the center of...

Thanks for all the responses. My understanding is improved. However, an ancillary question comes to mind. I have seen expansion loops that are oriented vertically and others that are oriented horizontally. A vertical expansion loop would seem to present a pumping pressure problem because...

Pipe loops are used to accommodate thermal expansion. I have seen many types and lengths but here is one example: https://www.engineeringtoolbox.com/steel-pipe-expansion-loop-d_1069.html I am a little unclear on why they can work. With any thermal expansion the stresses on the elbow joints...

Not necessarily poorly presented. It just seems to me that most textbooks/websites use exclusively a rigorous mathematical approach without being supplemented by intuitive examples. The original poster apparently has difficulty in seeing through the mathematical thicket.

No. I was not saying anything at all about you personally. I was talking in general terms about a possible reason why a lot of people have trouble with thermodynamics. It may be that the subject is presented with too much mathematical derivations and not enough intuitive examples.