Low body fat or high basal metabolic rate or lucky genetics all help with rapid purge. I know a guy who hasn't gone more than 36 hours in the last 9 years without a joint - he gets tested once a quarter and presents clean every time - he's either the luckiest bastard breathing or he has freak genetics. I don't know for sure - but the test kit manufacturers would presumably need to wiggle a fair bit of leeway into a nicotine test so that they weren't false positive identifying people who got secondary exposure walking into the office or something. Balancing false positives vs robust detection is notorious for leaving leeway in the testing systems that let a lot of people get away with shit. Depending on the manufacturer of the test and where you are - the tolerances for being considered a successful detection change. In the UK where something like 98% of all currecy in circulation has been exposed to cocaine - the detection tolerances have to be a lot higher than in Australia where coke is relatively rare.
Is there any way I can test the vibration absorbing properties of different woods (and wood/carbon fiber and wood/foam) laminates? Or is there some information out there already? I'd appreciate anything there is.
So I'm taking an OChem class. My teacher sent out our first homework assignment, which wasn't too hideous, but the last question is kinda bothering me. I've posted it for your perusal. Now, of course we've done the absolute bare bones discussion on this using very easy, simple examples in class, so the molecules she put up are a bit beyond anything we've talked about. I put up my answers too, just to see if I've got it right. I didn't bother with the bonds involving hydrogen, but should I when they involve nitrogen or oxygen? Thanks.
That looks fine to me. I assume they don't want you to mark the polarity of bonds to hydrogen? That would be pretty unnecessary. Aromatic rings are electron-rich so you might mark those bonds as polarized, but I think that's beyond the scope of the assignment. If you've never taken an organic class before, it's not hard, it just gets a bad rap. Edit: noticed the part about hydrogen. If it's bonded to N or O, polarize that shit. If you have questions just refer to a table of electronegativities. Generally speaking it goes (in descending order) F-O-Cl-N-Br-I-S-C-P-H.
OK, time for my next OChem homework. I'm 99% positive I got them all right, but I really want to kick ass in this class, so I'm posting it for you guys to look at. We just did the halogenation yesterday in class, so that one might be fucked up. Not sure.
Question 4, subquestion 3-are alternate chair conformations considered rotamers? Other than that it looks fine, very minor thing about your axial substituents though-they're supposed to be parallel to the C2-C3 bonds relative to the substituent. I'm 99% certain the halogenation is fine, but I'll check in my organic book when I get to lab. Are you just taking one semester? Second-semester organic is the hard part, first semester is child's play and you shouldn't have any trouble kicking ass in it.
I doubt it really matters, but the other termination step is the radical hydrocarbon reacting with another radical hydrocarbon. Granted this will basically never ever happen because of the steric hinderence... Ochem is not much fun.
The internet is one of those things that I'm very familiar with, I use it every day, and yet I have no idea how it actually works. What I'm wondering is, could the internet ever "break"? I mean I'm sure it's not like South Park with that one giant router or whatever it was, but are there several main servers? Or is the internet pretty much stored/maintained in tiny pieces all across the world? To those of you who know about this stuff, that was probably a pretty stupid sounding question. Whatever.
Yes. Hypothetically there are some events that could 'break' the internet. But those events move from wildly implausible (massive and major compromise of root name servers) through to astronomically improbable (Some kind of nuclear/solar event that soaks the entire world in an EM pulse so strong that it destroys the world's electronic devices). There are very robust safeguards, including backup proceedures and recovery steps that would allow for the recovery from pretty much any of these events. What's more likely than a single clean break would be significant damage to key infrastructure that causes the rest of the world to grind to an unusable. A spectacularly stupid US government or major security event on US soil could do serious damage. 9/11 hit global infrastructure pretty hard - although very few people actually gave a fuck about it, all things considered. That sort of event still has potential to impact a big chunk of the world's internet users. With any of this shit though - assuming that there's a population surviving after the event that causes the issue - and assuming global manufacturing capability isn't completely disabled - international communications networks will be a major restoration priority for the foreseeable future of the species - and recovery will always be possible. If some kind of stellar phenomenon (or gross act of stupidity) managed to compromise a majority of undersea cabling and take out a majority of satellite communications infrastructure - that would probably be the most expensive/longest lasting issue. But it's wildly improbable that both infrastructure channels would go at once unless there was an event along the lines of a war between the US and China with some kind of world war two 'any sacrifice for victory' mentality ingrained in both sides. The Stuxnet worm is the scariest thing to hit IT in a long time - it's a serious threat to real world infrastructure - like power stations and dams - that exists solely as a software entity and may be being run by a malicious government or terrorists (although probably isn't). And that could conceivably take out national power infrastructure or something.
Does anyone have experience with airplanes, more specifically model airplanes (as in sub 6ft wingspans). I have some questions that I need answered and have no idea where to start with them. thanks
String Theory is fucking confusing, and isn't really relevant to layman terms. String Theory is a proposed Theory of Everything - and you need to get your head around that concept to get your head around String Theory. a ToE is meant to be a full and complete description for everything that can be observed or tested - a complete understanding of the physical universe - so it should describe everything from gravity to black holes to quantum distortion to why red headed children are funny looking. It also means that the people who describe it are going to be some of the most famous people in history. So the science dorks who are leading the Theory of Everything investigations all started out as inspiration for The Big Bang theory and then most of them got too arrogant and self absorbed to be funny. Most proposed Theory of Everything models are all about reconciling the theories of something else - or taking the things that we think we know, but that conflict with each other and finding a way to make them one happy extension. The best example is that General Relativity doesn't reconcile well with Quantum mechanics. One of the big problems with String Theory is that there are predicates like dimensions that can't be observed, which makes developing an experiment to prove the cornerstones of the dominant theory of everything models current impossible or at least so impractical that it's mostly just a bunch of physics geeks jerking off about who'd win in a fight, superman or batman. String Theory isn't really something that most people should care about, it just sounds cooler than M(embrane) Theory, which is a unification theory that reconciles a bunch of other string model theories and suggests that everything is actually made up of membrane like strings, that are really 1-dimensional slices of a 2-dimensional membrane vibrating in 11-dimensional space. And that's as close to a laymans explanation of string theory as you'll get. If you accept that theory as being sufficiently plausible that it's worth testing - you're still kind of not going anywhere. Because most of those dimensions are predicted - which is to say we don't have any evidence that they exist - but if they don't - m-theory falls apart. Also, to quote Wikipedia, 'String theory as it is currently understood has a huge number of equally possible solutions, called string vacua, and these vacua might be sufficiently diverse to explain almost any phenomena we might observe at lower energies'. Other people argue that String Theory is testable because of the AdS/CFT connection. AdS/CFT is a much less controversial area of string theory that can plausibly be tested and there are some LHC tests that are probably going to happen to test them. But if you thought string theory was confusing - take something for your headache before you try reading the AdS/CFT articles.
If you're interested in string theory, the book by Brian Greene (The Elegant Universe) does a pretty good job of putting the theory into layman's terms (considering how complicated it really is).
Ok so I'm taking physiscs with Calculus this year and we just dipped into 2D motion. We've been given this equation and I'm trying to figure out how this works. I understand that V_x is unaffected by gravity but is dependent on time. So we got this cliff of unknown height, with an object being launched off it at 30* time is 3 seconds, and the ball hits the ground 15m out from the cliff edge. So we need to figure out how high the ball travels over its arc and I think how high the cliff was. Any help would be nice, the equation we got doesn't seem to take into account how high Y_0 is... Y_f= -h-V_0sin(theta)T+ 1/2gT^2 I plugged everything in and got a height of 36.6m which I'm inclined to believe but I'm not really sure.
y_0 (or the height of the cliff) appears to be the h in your equation. Though from your equation it looks like the positive y-axis is pointed down which is kind of odd, but as long as you're consistent with your coordinate system the only change is going to be the sign of the final number you get. It sounds like you're looking for the apex of the balls travel? To find that you want to take the derivative of the y position equation. This will give you v_y as a function of time. At the top of the ball's flight, v_y will be equal to zero. Find the time at which this happens, then plug that time into your y position equation to get the value for the top of the flight.
Awesome thread. I have a bunch of things that have been puzzling me for ages but I've never bothered to go down to the local university and ask someone about them. Forgive me if any of these are repeats, there's 14 pages to this thread and I'm not reading them all. 1. The internet. I've done some looking but I can't find a comprehensive explanation of exactly how the internet works anywhere. I understand that there are a bunch of servers in the US somewhere that control it all somehow. What exactly does that mean? 2. Computer data compression. If computer data is all stored as 1s and 0s on a hard disk, how is it that I can zip a file and have it require less 1s and 0s without losing any information? Like the internet, this is probably something that I'm lacking even basic knowledge in. I'm great at using computers, but I sure as hell don't know how they work. So if anyone can link to a layman's guides for this kind of thing, that'd be much appreciated. 3. Global Warming. What's the actual scientific concensus?
First, go search for threads dedicated to global warming. Second, learn how to use google and wikipedia. All that stuff is covered very well by those and other popular sources. If you're not going to be bothered to go through the thread and lurk a bit to get an idea of this board and thread, fuck off right now. This thread isn't meant to be a first stop to answer simple questions for retards.
I was thinking a DCH response might be in order. You'd have 24 hrs to succinctly provide well thought out, unique responses to those questions or you're banned. Seriously, it took him longer to write the fucking question than it did for me to find simpleton level explanations to each of them with google.