bernulli

Why wouldn't there be any temperature change in ideal gases? When I compress an ideal gas in a bike pump, it heats up; when I expand it through a nozzle, it cools down. Often I can approximate these processes as isentropic, and then the temperatures are uniquely determined by the expansion as either a function of pressure ratio T2 = T1 (p2/p1)^(g-1/g) or volume ratio; T2 = T1 (V2/V1)^g, where g is gamma, the ratio of specific heats.

https://en.wikipedia.org/wiki/Isentropic_process

[edit: typo]

Also try to read my other comment, the difficulty is precisely my point.

I don't see how 'laser in the study is moving with the projectile' is in any way, form, or shape ambiguous.

And the $2000 price point is not from the paper but from your own post.

Try to read my comment, I never 'assumed otherwise', the difficulty of having the laser as payload is exactly my point.

Yes, it's 'moving with the projectile'. How does that make it easier?

The laser in the study is moving with the projectile, so I guess even for $2000 you won’t be able to have a 30 km altitude, Mach 6 flying object with perfectly controlled laser launched from a trebuchet.

It absolutely is, and will then drive differences in reference area, thus affecting the drag of the object.

You’re missing nothing, you’re correct.

But very much in inertia, which is acting against the drag, trying to sustain its initial velocity.

https://en.wikipedia.org/wiki/Ballistic_coefficient

Thanks for contributing to the discussion!

I think you have entirely missed the topic of this thread: the comfort of obtaining the book. The list of steps addresses exactly that, whereas reading the book has nothing to do with it.

Couldn't agree more. For me certainly not worth the hassle to save $3 on a reduced book that will magically appear on my kindle after I clicked 1-click-buy, compared to pirating it.

I remember how upon Radiohead's release of 'In Rainbows' people would argue that the fact that people would still download an album from Kazaa that you can legally download for free from the artists website proves how rotten everyone is. No - it's just that the UX of doing it legally sucked so much more.

I'd say prison is pretty low on the 'comfort' scale, certainly lower than '1 click buy'.

What's the legal side of this?

That one https://en.m.wikipedia.org/wiki/Tatra_77 also doesn’t look like either Tropfenwagen or Schlörwagen.

I don’t doubt there are many cases of blatant copying in technology, but I am having trouble to see any connection between either Tatra and the cars discussed in the post. Also: the “Czechoslovakian” Tatra linked to was designed by an Austrian and a Hungarian.

I don’t understand your comment. Neither the Tropfenwagen nor the Schlörwagen look anything like the Tatra you linked to.

I don’t understand your comment. What does Raptor have to do with CFD method developments? What is the frontier? What does it mean to run out of frontiers? Shouldn’t there be more resources rather than fewer?

A bit big for a thruster, no? https://en.m.wikipedia.org/wiki/NERVA

I don't see that as a reasonable constraint - nuclear propulsion does not need combustion, thermo electric does not need combustion, and there's also things like cold gas thrusters, laser ablation etc. etc. etc.

That was 6 years ago, hard to say what remained of that ambitious goal. Also, these guys aren’t with SpaceX anymore.

Sure, and an engine that wouldn't need any fuel/power at all would be even better - the question is, what is practically/theoretically achievable.

But I guess the fact that everyone is avoiding the elementary question of 'how much can a transportation system transport' tells me all I need to know about the practicality here.

In addition to calling my question 'wrong' - can you also answer it?

Also, if your 'correct' metric were right, then everyone would walk. Does that solve the problems flying does? I don't think so.

[edit]: Also, I guess your metric explains why everyone is only taking the bus or train, and private transportation does not exist?

Range is one thing - what is the passenger capacity of these planes?

What can I say. Maybe drawing that flow chart really would be helpful for you. It's a valuable skill, being able to follow a thread or a conversation, and trying to understand the back and forth between statements and arguments may come in handy some other time.

That's true, I hope you're not waiting anymore.

If you want to understand this thread, I suggest you start at the start.

Hint 1: I gave you the name of the person I answered to.

Hint 2: No matter how often you repeat it, it wasn't you.

Hint 3: Maybe it helps if you draw a flow chart of the different statements in the conversation!

But, see, don't worry. Because you jumped into a conversation between the post I replied to and myself, I assumed you had to add something to that conversation. I realize that I was mistaken and you just swooped in to offload some unrelated fun fact. My bad, won't happen again!

One day you'll understand how a thread works! Don't give up hope!

I didn’t realize you were daniel-cussen - but it looks like you’re merely overwhelmed by how a forum works. That’s fine, but maybe dial down the smugness.

No, but the post I replied to, and apparently you felt the urge to reply to my comment. But I now understand that you did not intend to contribute to the discussion, thanks for the clarification!

Sure. And none of this prevents hydrogen from escaping.

Have you worked with hydrogen? Being less prone to leaving than He is an extremely low bar and very far away from the claim that it doesn’t ever diffuse through anything.

Why would the hydrogen not escape?