colcob
colcob t1_j87vtch wrote
In a hypothetical situation in which the tube is inert, clean, empty and open and one or both ends, then yes it will be full of air of the same constitution as the surrounding air.
In a real life situation where it could be full of rotting stuff, degraded materials etc. then at 400m long and 0.6m diameter it’s very possible that air contaminants in the middle could be build up enough to be hazardous.
colcob t1_j5zkjlf wrote
I feel the graphics card situation has really changed my perception of the cost and power consumption of computer components. $699 and 250w seem pretty mild really.
colcob t1_j5sdytd wrote
Reply to comment by Old_comfy_shoes in If I had two cups of water, one normal size and one as big as a swimming pool and stirred them both with proportionally sized spoons, would the larger pool of water keep spiraling longer than the smaller? by r3volc
So by rotational rate i mean the angular velocity, ie. degrees per second, RPM, not the tangential velocity.
I guess I would stir a cup of about 1 revolution per second, so I'm imagining that if you stir the swimming pool cup at 1 revolution per second, the water's going pretty damn fast at the edge!
colcob t1_j5pe6hk wrote
Reply to If I had two cups of water, one normal size and one as big as a swimming pool and stirred them both with proportionally sized spoons, would the larger pool of water keep spiraling longer than the smaller? by r3volc
Yes. The rate of slowing of the spinning water must be a function of the kinetic energy of the water against the drag of the side walls.
Even if the max velocity of the water is the same in the pool (ie a very slow rotation rate) then the energy of the water will scale somewhat with the volume of the water, ie cubicly, while the drag of the walls will scale somewhat with the area of the side walls, ie. squared, therefore the larger the cup, the more the kinetic energy of the water outweighs the drag of the sides.
If you do actually stir at the same rotational rate, then as the other commenter says, the max velocity of the water will be very significantly higher than in the coffee cup, and as energy scales to the square of the velocity then you'll have vastly more energy proportional to drag than in the coffee cup.
Plus anecdotally, as a kid we used to run around those circular backyard swimming pools and get the water spinning faster and faster, and they kept going for ages!
colcob t1_j2k9oe7 wrote
Reply to Researchers have discovered a new situation from the everyday environment where our crucial ability to perceive what is truly vertical is compromised: when our body pitches (body pitch) and moves at the same time (body motion) by giuliomagnifico
I’m going to guess this might explain why those posters on the escalators to the London Underground never look vertical ( although I think it’s more likely a visual effect caused by the adjacent diagonal lines)
colcob t1_j1d1cwg wrote
I’m not quite sure why they’re panicking yet. ChatGPT is notably hopeless at providing correct answers to questions of actual fact.
colcob t1_iwp2c3o wrote
A big drop of water floating in space could only have such pressure internally as would be caused by its own gravity. A rough calculation says that surface gravity on the mini water planet would be about 1/10’000th of earth gravity, so pretty small, but which would develop about 1.5 psi of pressure under 7 miles of water.
colcob t1_irdy4yp wrote
I can't really answer your question, but just wanted to clarify your 'radiation is not matter' statement.
3 of the 5 major types of radiation are in fact matter. Alpha, beta and neutron radiation are all particles of matter. Only Gamma and X-Rays are an electromagnetic wave.
As others have said, often it's that the radioactive material itself has 'stuck' to things, although Neutron radiation does have the ability to make make other materials radioactive.
colcob t1_je40mdu wrote
Reply to The Jobs Most Exposed to ChatGPT by PooPooRichardson
Accountants? ChatGPT can't even count, or add two numbers together.