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## plot explanation - did the world know about wakandan vibranium before the end of black panther?

it's possible that bruce, tony stark, and possibly howard stark already know about the wakandan vibranium. besides them, there are more people who tried to intrude and steal vibranium from wakanda. one of them is ulysses klaue, a guy ultron gets vibranium from.here are some references.captain america: the first avengerhoward stark: vibranium. it's stronger than steel and a third of the weight. it's completely vibration absorbent.steve rogers: how come it's not a standard issue?howard stark: that's the rarest metal on earth. what you're holding there? that's all we've got.avengers: age of ultrontony stark: if this guy got out of wakanda with some of their trade goods...steve rogers: i thought your father said he got the last of it?bruce banner: i don't follow. what comes out of wak...

## united kingdom - how can i ask if something's free, without looking stingy?

"is that extra, or included?"it's a way to inquire about pricing while not actually saying any specific word that is heavily financial in nature.or, simply, "how much is that?" by inquiring about the cost, you can be delighted if you find out its free.if it's more than what you want, just note, "no thanks, i'll pass."

## sensors - soyuz landing ground detection

how does soyuz detect ground to fire its retro rocket at the end stage? is there any paper/reference describing full entry descent and guidance algorithm and sensor suite used in soyuz?if soyuz uses sonar principle(just guessing), then one cant use soyuz to land on moon.if soyuz uses laser altimeter, then at such low altitude the time to return will be too small. i wonder if laser altimeter can detect such resolution. even if it does one will be pushing sensor to its limits. not a good idea.if soyuz uses stereo camera. then one cant land on night. the luna and surveyor series used a one extended ground contact sensor for engine cut off. soyuz does not definitely has it.so what is used in soyuz ? whatever is used in soyuz. is there any sensor which will be better than what soyuz uses ?

## regression - y must be normally distributed. where does this misconception come from?

'y must be normally distributed'must?in the cases that you mention it is sloppy language (abbreviating 'the error in y must be normally distributed'), but they don't really (strongly) say that the response must be normally distributed, or at least it does not seem to me that their words were intended like that.the penn state course materialspeaks about "a continuous variable $y$", but also about "$y_i$" as in $$e(y_i) = \beta_0 + \beta_1 x_i$$ where we could regard $y_i$, which is as amoeba called in the comments 'conditional', normally distributed,$$y_i \sim n(\beta_0 + \beta_1x_i,\sigma^2)$$ the article uses $y$ and $y_i$ interchangeably. throughout the entire article one speaks about the 'distribution of y', for instance: when explaining some variant of glm (binary lo...

## landing - when does an airliner switch from using the tiller to the rudder?

i flew for two 747 carriers that never bought new aircraft, and thus this answer applies to 747-100/200 aircraft as originally manufactured for a number of different airlines.the tiller is active when the aircraft is on the ground and the nose gear is compressed regardless of groundspeed as i remember.i've never heard of a pilot accidentally hitting it at high speed on the ground, but if they did it would scrub the front tires. it wouldn't appreciably turn the airplane.pilots did have to be wary of having their hand within the travel range of the tiller when a tug is being hooked up. ground handlers would sometimes work the nose gear back and forth a bit, and that action is reflected in tiller movement. if they do it quickly, the tiller will snap quickly and a hand in the way will get hu...

## pigeonhole principle - assume that we have six positive real numbers whose sum is 150. prove that there exist two of them whose difference is less than 10.

the smallest of the six terms must be more than $0$. if the differences of any two is at least $10$, then the second must be more than $10$the smallest the third must be more than $20$.etc.so all six must add up to more than $0+10+20+30+40+50=150$.so they can't add to $150$. they can be arbitrarily close to $150$ but they must be more than $50$......if the smallest one is $a = \epsilon > 0$ and then the next smallest is $b \ge 10 + \epsilon$ and then the next smallest is $c \ge 10 + b \ge 20 +\epsilon$. etc.the sum is $a + b + c + d+e +f \ge \epsilon + (10 + \epsilon) + .... + (50 + \epsilon) = 150 + 6\epsilon > 150$.

## ethics - laptop turned in to it support has a document with staff member's name. is it ethical for the staff member to read it?

i have to disagree with 99% of the other answers. as an admin assigned to recover data you can access everything imo, because part of the job is making sure that the data is readable/functional.to ensure that, you need to open a few files sporadically at least.it's also possible that this file includes information adressed to you, especially if it's in a location the client knows or hopes you will see, eg. the desktop or the folder you are supposed to rescue.if you rescue the data, but it turns out the rescue mechanism wasn't good enough to recover the data, then the client will send you the laptop again, complaining about your slacky work.if you rescue the data, but ignored the clients instructions written in the file (which might be extremely important), you might get fired or warned ...

## dnd 5e - mathematically, is an ac+2 better than attackers having disadvantage?

i would recommend the following reading material on how to understand the probability behind dis/advantage. probability for gamers (wall of text crits you for 500dmg, yeah this guy is thorough).that article does a great job breaking down the numbers but i will rehash a bit.bracers of defense is a simple calculation an effective increase of 2 on the target die, base 10% difference statistically.disadvantage gets a bit muddier and, well it depends on the target number required on the unmodified roll.example: if your ac is 18 currently and you are facing a goblin with a +4 to hit you then he would need an unmodified roll of 14 on the die to hit you. this means that statistically disadvantage provides the equivalent of -5 or -4 depending on if you round up or down on the probability.if you ins...

## reference request - contemporary philosophy of mathematics

it's not entirely clear to me what you mean by a "position." under the most obvious interpretation, things like platonism, logicism, formalism, intuitionism, finitism, etc., are "positions." however, it seems you are attempting to probe the community of practicing research mathematicians for the "positions" that people currently hold. my anecdotal sense is that the majority of working mathematicians do not have a clearly articulated "position" that they adhere to, since they're mostly busy doing mathematics, and doing mathematics typically does not require taking any of the above "positions." (people who work in areas such as logic and set theory are an exception, since they typically have thought hard about such questions, whether or not they publish anything that is explicitl...

## dnd 5e - how can a boss enemy prevent being the most obvious target?

the problem that usually causes this scenario is that the players assume two things:the big bad is the most (imminently) dangerous enemy in the roomkilling the big bad will end the encounter quicklyand neither of these actually have to be true, or they don't have to be completely true.you can give your super-necromancer control over some spawn of kyuss (volos guide: 192), where failing to defeat the spawn before trying to engage the necromancer will result in the party having a much harder time with things.you heroes think you can stop me, but you will just end up strengthening horde with your undead corpses! now why don't i introduce you to my newest creations...an orc warband leader can have a ton of other orcs under his control, and let them loose on the party before making his grand ...

## science based - the gun which makes no sound

there are already a wide variety of surpassed weapons out there. russian "captive piston" rounds are likely the best way to use conventional weapons (simply load 9mm captive piston bullets in a glock, for example), so long as you make allowances for the reduced range and penetration compared to normal rounds. this isn't limited to pistols, the us navy developed a captive piston 12 gauge shotgun shell during the viet nam war. the us army also experimented with captive piston and other silenced weapons for "tunnel rats".12 gauge "telecartridge"perhaps the best place to look for inspiration would be some of the assassination weapons designed in the second world war. in addition to subsonic rounds, many used locked mechanisms so there would be no noise as the action cycled, or extreme v...

## ethics - what are the ethical problems with flipping a coin to decide between saving 1 or 5?

this question is strongly related to the current debate about autonomous driving. when a crash is unavoidable, how can/should the car's computer decide what it should crash into, the group of five to the left or the single person to the right?the answer is more or less obvious: it can't make an ethical decision.why is that? simply because the car's computer has no information about the individuals it has to decide over.and i think that is the point the original statement makes: when you have no information about the members of the two groups you cannot make an ethical decision. hence, you should not make the decision and can only randomly pick one alternative.extreme example: the larger group may be a chain gang of convicted serial killers working at the side of the road, and the smalle...

## code golf - area enclosed by perimeter loop

expects the second input format.a=>a.map(k=>r+=~~[y+=~-'121'[a=a+k&3],,-y][a],r=y=0)|r try it online!how?this is based on the formula already mentioned by @ngn: a = σ(xi - xi+1)yi, which can also be written as σdxiyi where dxi is either -1, 0 or 1.we start with r = y = 0.we keep track of the current direction in a: | a=0 | a=1 | a=2 | a=3 ----------+------+-------+------+------ direction | east | south | west | north dx | +1 | 0 | -1 | 0 dy | 0 | +1 | 0 | -1 it is updated with a = a + k & 3, where k is the current element of the input array.because a initially contains the input array, a + k is coerced to nan on the first iteration and then to 0 when the bitwise and is applied. this means that the first direction change is actually ignored and we always start headin...

## political theory - what is the difference between a separatist and a rebel?

in the context of independence movements, separatists are individuals who want to take a landmass out of the administration/control of a country to form a separate country or to join the landmass to another country.separatists can be of two types:violent separatists are people who use violent means (usually armed struggle) as a tool to become separate from a country. e.g. irish republican army.peaceful separatists are people who use politics to get separated from a country. e.g. catalonian separatist movement.violent (armed) separatists are called rebels1, 2.note. rebellion may exist external to the concept of separatism. for instance, a group of army soldiers may commit mutiny against the army headquarters irrespective of the cause. that would also be a rebellion. e.g. bangladesh rifles r...

## riddle - anagrams all over this place

similar to @twobitoperation's answer, it could be: djibouti, djiboutiprefix=djibouti, suffix=djibouti, infix=outidjib a key distinction between the answers being: djibouti is a country, but washington is a state (edit)since that was the best i could come up with, one note about this puzzle: the speaker says "my [prefix|suffix|infix] is anagram", not "my home" or anything else referencing a location. not sure whether that's noteworthy/intentional/helpful, but thought i'd mention it.

## worldbuilding resources - is there something like "open source elvish"?

all elvish is (probably) open source (in the us)there is a real legal history of battles over open source languages, two threads of which are relevant here. the first is that the us court system has definitively ruled that it is not a violation of a constructed computer programming language's copyright to write a new computer program using the same language and grammar. although there have been no definitive cases regarding 'conlangs' (constructed languages), the other thread is the situation of the legal battle over prelude to axanar. general background informationthere was a journal of tolkien's linguistics titled tyalië tyelelliéva, originally hosted on geocities and now gone. this journal published original works in tolkien's languages in addition to other analysis, but evidentl...

## requests - how can i ask (or determine) if someone on the phone is real without offending them?

first of all, spotting a recorded message is easier than spotting ai. by "recorded message" i mean the systems that play a full message and then have some very limited ai to interpret a yes or no response. such messages are usually delivered very rapidly so that you wait until they are done before responding.i've had the irritating experience of believing it was a real person inviting me to an event of some kind, with their inquiry ending with "will you be coming?" when i began to explain why i wasn't coming, i was interrupted with a recorded, "i'm sorry, i didn't understand that. please say 'yes' or 'no.'" very annoying.rather than waiting for the complete message, now i will interject as they begin their spiel. "hello, this is amy calling from ____ to invite you to...." a...

## bitcoin - a friend asks me all the time to pick up money for her (western union, moneygram)

so just to be clear, she gets so many of these ~\$500 transactions she can't even make the time to show up and collect them all? yet, she still holds down a day job cutting hair? you are on here asking if this is strange because well, it seems very strange. "bitcoin" something something is a convenient way to explain away strange income sources. it's mentioned in the media as some mysterious source of wealth for the lucky few, who really understands it?does this friend cut the hair of the wealthy, influential or socially mobile at a swanky salon? does she own her on business, as in the entire business and not just rent a stall? or does she grind out haircuts in a strip mall? the thing about unreported/illegal income is you can't just quit your day job. it raises too many questions. leg...

## science based - the gun which makes no sound

it basically already exists.behold, the russian s4m pistol:this firearm, like the others in its family, uses a unique piston-driven cartridge. if you look in the cutaway cartridges, you will see this piston behind the bullet. when propelled by the gunpowder charge at the rear, the piston rams the bullet forward, propelling it down the barrel.when it reaches the end of its stroke, the piston seals on the front of the cartridge, preventing any noise or gases from escaping. the only noise in the action comes from the internal striker system, and the mechanical friction between the bullet and barrel.as long as the bullet is subsonic (and in this design, it is) there will be no sonic boom as it passes. while there might be some noise from the striker, at most it is a 'click' rather than the l...