Everything posted by swansont
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Living away from earth (split from Mars gravity issue)
You also want the gradient to be acceptable as you move toward the rim, or you'd end up with a situation where you had 1g at your feet but significantly less at your head. (consider a 2m radius, for example)
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Living away from earth (split from Mars gravity issue)
Why would storage space be limitless on a space station?
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Exploiting E=mc^2 of matter can be understood in a simpler way
I'm not sure what you mean here. Uranium density is not lower, or smaller. Logic sequence? That has nothing to do with the energy released in a reaction. Also, I didn't hide any article.
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Exploiting E=mc^2 of matter can be understood in a simpler way
Chemical reaction are in general much lower in energy than nuclear (eV vs MeV scales, i.e. a factor of a million). I know of no batteries, or any electrochemical reactions, that convert grams of mass into energy. As you point out, 1 kg is almost 10^17 Joules, or 25 billion kWh. So a gram is 25 million kWh. A battery might give you a couple of amp-hours at 1.25V, or something of that order of magnitude, which is just a few Watt-hours of energy. That would be around a billionth of a gram. Uranium (U-235 in particular) is used because it readily undergoes fission and can be controlled under the right circumstances. It gives you this energy at the nuclear, rather than chemical, scale.
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Comparing Corona Virus Success Stories with Abysmal Failures
What is ideological about this?
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James Webb Telescope and L2 Orbit Question
The GAIA mission encountered more micrometeoroids than expected. “the spacecraft is being peppered by far more micrometeoroids – tiny specks of space dust – than had been anticipated” https://www.newscientist.com/article/dn25925-galaxy-mappers-first-discovery-surprise-space-debris/
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Mars gravity issue
! Moderator Note Let’s stick with the topic, which is Mars and the problem that low gravity presents
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Is The Universe Infinite?
! Moderator Note did lordofscience read the rules they agreed to upon joining? (specifically 2.7, which says not to make posts advertising your website)
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Newton knew that his law of gravity is not final
No. The geometry is curved; gravity exists even with no body to experience it.
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SCUBA weights
That would work, if you could do it. But there's no way of "collapsing" the water, since it's already a liquid. My point was that if you were lugging around extra mass, then you will always be lugging around extra mass, regardless of its density.
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Brain teaser: travelling faster than the wind.
There is the additional caveat of going directly downwind. A sail won't do this.
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SCUBA weights
Mass-wise this is a non-starter. It's basically conserved at this scale. The density issue is another thing. You want the opposite of a submarine filling the ballast tanks from the compressed air tank. The problem is that you are starting with a positive buoyancy, so you will always need that extra mass, regardless of the density, unless you can figure out a way for the human body itself to become more dense.
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Brain teaser: travelling faster than the wind.
I think the first reaction is thinking the propeller is driven by the wind, and powers the wheels. Such a device would not go to faster than the wind, because the thrust would drop to zero when the vehicle speed and wind speed are equal. I think that's the initial reaction of the people saying it's impossible. These are losses and would initially be ignored. The first-order questions are what is the energy of the cart, and what is the energy extracted from the wind? At the point where you are going downwind at the speed of the wind, the speeds are equal. So the mass of the air involved must exceed the mass of the vehicle, which suggest you need a big propeller, since you want to maximize that mass difference. A big propeller means the "column" of air has a large volume.
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How best to disinfect a plastic beverage cap that fell on the floor?
Do you worry about this when eating food with your hands? Assuming that you wash your hands with soap, that it. The rinsing effort is similar, as is the risk of ingesting soap.
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About plagiarism
Plagiarism is passing off the work of someone else's as your own. It is a form of cheating - you are taking credit for someone else's work. Buying an essay is one form of plagiarism. In some cases it's the least useful form of cheating, since giving proper credit to the source shouldn't diminish your own work in any way.
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How best to disinfect a plastic beverage cap that fell on the floor?
Have you considered washing with soap and water, with proper rinsing afterward?
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Brain teaser: travelling faster than the wind.
I recall a device claiming this perhaps 10-15 years ago. There was some controversy initially owing to some confusion about the description. It was a cart with a propeller that was driven by the wheels, but the propeller was sending air backward (so it was not the wind turning the propeller and providing energy to the wheels), which means the propeller was acting somewhat like a sail in capturing its propulsive energy, and also providing thrust. The propeller thrust depends on the ground speed, and as long as you capture enough energy from the wind it could work. So, big propeller, low mass. edit: link rot was thwarting me, but I finally tracked something down https://boingboing.net/2007/02/06/video-can-a-vehicle-.html https://www.youtube.com/watch?v=aJpdWHFqHm0
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Which emails can be used to register with historum.com?
Surely that have contact info so you can ask them.
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Not from planet earth, but interestellar dust...
Possibly silicon. Whatever they used for a substrate.
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What is this?
You're going to have to give more information than this
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Is there a name for this indentation in the triceps?
I think I googled “name of indentation between bicep and tricep” First hit. (incidentally, mentioning that you’ve at least tried a search is worthwhile)
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About plagiarism
It’s hard to envision that just compiling others’ words would make for a coherent paper. Of course. We see that here in the HW section with people who just want the answers.
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About plagiarism
There’s nothing wrong with using pictures, drawings or passages made by others (sometimes it’s unavoidable) But you need to give citations for them, and not present them as your own work. A big part of the problem, IMO, is that they are given a pass early on. It also seems to me that the younger crowd was more prone to sharing music and ignoring copyright back when napster, etc. were big. Maybe there’s a connection.
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Is there a name for this indentation in the triceps?
Ah, Google “The space between the biceps and triceps forms two grooves (medial and lateral bicipital grooves)” https://www.kenhub.com/en/library/anatomy/biceps-brachii-muscle
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Is it easy to shade the Earth for cooling?
No? I can see where I said it. “A shield as described would be send the net radiation perpendicular to the surface. Basically half would head to the earth.” That was part of my explanation as to why it wouldn’t work. I said “the shield as described” so it should have been clear what I was talking about