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Oct
6
comment How does gas spin the turbine in a jet engine?
@Ethan: No, the fuel makes the air hot, which makes it big, which makes it blow out the back (because the back is just a big hole). The turbine is just a fancy windmill.
Oct
6
comment How to calculate thrust from opening a pressure vessel in space?
As a round approximation, it would just be the pressure times the area of the hole. Of course, if it's off-center, which it will be, the astronaut will also spin wildly.
Oct
6
comment Pressure variation
@JamesEadie: if the volume remains unchanged, that means as you stretch the pipe its diameter must get smaller (you said - no volume change), and that means the only pressure change will be at the bottom, because the height of the fluid column above it has increased.
Oct
5
comment If pressure in fluids is caused by the elastic collision of fluid molecules then why does the pressure increase with depth?
@Faizan: Open a tube of toothpaste. Press on the side. Toothpaste comes out of the opening. That is perpendicular to the direction of your pressure. That's what happens in fluids - the pressure goes quite easily "around corners".
Sep
30
comment Does an ion thrust engine consume more energy as it speeds up?
@DewiMorgan: I had it wrong. Thanks.
Sep
29
comment Does an ion thrust engine consume more energy as it speeds up?
@ChrisDrost: Right. Thanks for pointing that out.
Sep
25
comment How does a boomerang behave in microgravity?
Maybe when my grandsons goad me into entertaining them :) I'm leaning more toward the helix idea because I would expect the axis of rotation to precess in a circle, just like a top slowing down.
Sep
25
comment How does a boomerang behave in microgravity?
I especially liked your second link, where you show how to do a miniature boomerang. This could be tried in the international space station.
Sep
23
comment How do propeller blades rotating through air accelerate it to provide thrust?
Have you ever stood in front of an electric fan?
Sep
21
comment A Confusion in Rotational Dynamics
See calculating the center of percussion.
Sep
21
comment Trying to understand jet engine
There's a simple way to understand this. Suppose there were no turbine. Suppose no compressor - just a cylinder of pressurized air, exiting by valve into the open-ended combustion chamber, where it is heated - thus expanded. Which way will it flow? Toward where the pressure is less, of course. Check this, where a piston engine drove the compressor.
Sep
16
comment How does a 1,000 mph car maintain vertical stability with tiny front wings?
@tpg2114: at mach 1.4, aerodynamic forces far exceed weight. As far as bumps, I assume the designers know they are designing a low-altitude aircraft. So the center of mass has to be forward of the aerodynamic center (as the tail shows), so that when there are lateral or vertical disturbances, the natural tendency would be to damp them out.
Sep
11
comment Does air travel through a car when you are driving through air?
@Ethan: When you learn some physics, this is an excellent site with friendly, helpful, very knowledgeable people who will be glad to answer your questions, even if you are new to the subject. You could in fact get an answer from a world leader. For this question, you should just be aware that, for the most part, gasses and liquids do not flow through solids.
Sep
7
comment How does dark energy allow the universes expansion to accelerate?
Check out Alan Guth.
Aug
25
comment Whether there is any relationship between the frequency of an input signal and the frequency of it's fourier transform?
What do you mean by "FFT frequency"? FFT converts between time or space domain and frequency domain.
Aug
24
comment What are the biggest reasons that Cars get higher Land Speed Records than motorcycles'?
According to the link in @Daniel's answer, some cars are 3 wheels, so it seems like it might be possible to go to 2 wheels (with skids or something for low speeds). I don't quite understand how this would be helpful, though, since it's all about engines and aerodynamics.
Aug
22
comment Determine beat frequency
First try it with two frequencies close together. Then try widening the difference.
Aug
20
comment Why does everything spin?
@rmhleo: Right. I was only answering the part of the question about classical mechanics.
Aug
17
comment Infinite Accelatation
You should make it clear that when your "high speed makes time slow down" is only true from the point of view of the observer. You do not yourself see time slow down and acceleration getting harder. i.e. it doesn't take you longer to do anything, as measured by the clock you carry.
Aug
16
comment Hard Drive Air Bearing Questions
I just googled "hard drive air bearing" and a ton of stuff came up. Why don't you start there?