# ewmon

Senior Members

1295

1. ## Bullet Dropped vs Fired

I can see the diagram in your quote. It's background is blue. You can't see it? Here's its URL — http://www.nennstiel-ruprecht.de/bullfly/fig15.gif It actually shows the Magnus Effect and the resulting sideways drift, but the gyroscopic stability is clearly shown.
2. ## Serial dilution problem

The word "serial" in "serial dilutions" only means that the next dilution is made from the previous dilution, and not that the dilution factors are the same. However, it is true that many or most serial dilutions that you will be asked to perform will have the same dilution factor (at least that's been my experience). So, line up the dilutions in decreasing order of concentration, and perform the-next-from-the-previous dilutions individually. 10mM →1.5mM → 0.5mM → 0.25mM → 0.10mM → 0.05mM Alternately, in the situation you describe, a non-serial method could be where you make all the dilutions straight from the stock solution, but they would not be serial dilutions. 10mM →1.5mM 10mM → 0.5mM 10mM → 0.25mM 10mM → 0.10mM 10mM → 0.05mM
3. ## A sincere apology.

Thank you for sharing. I never know what to say. She kept it from you to spare you the pain. What a wonderful friend! Don't let her shoulder the burden alone, but don't let it define her either. You must now exercise your courage and show her that you can handle it. This will support her immensely in an emotional way, which will also help to give her both of you the best prognosis. The only thing any of us ever has is the present: the past is gone forever, and the future may never happen. This reality has become unavoidable to you in a very personal way. Treasure the present. ... and forgive me for waxing philosophically.

I think you're on the right track. 4x + 6∙4–x = 5 You set 4x = a Then you thought 4–x = 1/(4x) Good! That makes 4–x = 1/a, and so, you've simplified that term too. So now you have a +6/a = 5 You don't like this? Go ahead and solve it. It will start to look familiar as you work through it. You will grin, honest. After you solve for a, then solve for x.
5. ## Bullet Dropped vs Fired

Okay, I'll accept parabolic. So, why doesn't the bullet's spin stabilize the bullet? The angles are exaggerated in the diagram below, and it exists for bullets fired horizontal, although rather slightly. The gyroscopic effect diminishes the bullet's tractability by the air, and the bullet attitude will remain mostly horizontal, while (as you said) its trajectory angles downward, so the angle of attack is non-zero which produces lift, making it drop more slowly. I compared it to a non-spinning bullet, which is more tractable, and will angle downward, typically presenting a smaller cross-sectional area, and thus less drag, and it will drop faster.
6. ## US Government Shut Down - new elections for senate and house of rep.?

After the last federal shutdown, the government the taxpayers ended up paying the furloughed employees for their time off, so it turned out to be a paid vacation for the non-essential employees. How messed up is that? It's the seriously-burdened essential employees (armed forces, ATCs, etc) who need a vacation. At least Congress is not on vacation — but they are out to lunch. Three strikes and you're out! The 2007 Global Financial Crisis The 2013 US Budget Sequestration The 2013 US Federal Shutdown Vote the incumbents out.
7. ## On The Mistakes Actual Scientists Make

Remember the Italian seismologists prosecuted for the 2009 L'Aquila Earthquake.
8. ## US Government Shut Down - new elections for senate and house of rep.?

Ditto, just like the Italian government collapsing. We've had enough of these boneheads. They were elected to cooperate together, not compete against. All the representatives and senators should be fired, their privileges and pensions revoked, and new elections held. Almost guaranteed that we'd never see a government shutdown again.
9. ## The Secrets of Stealth

I anticipate that some sort of language difficulty exists here somewhere. What does "radio signature" mean? What does "thermonic" mean? What does "thermonic dispensation" mean? What does "a 90 degree angle towards the bottom of the craft" mean? What does it mean that "The intent of the dampener is to cause [the] heat ... not [to] escape away from the aircraft." What does "C/RE7" stand for?
10. ## Bullet Dropped vs Fired

Let me horn my way in here and say that the results (ie, time to reach the ground) between a fired and dropped bullet is mixed. For example, a bullet fired from a rifled gun will spin rapidly and acquire gyroscopic stability, causing the bullet to remain horizontal. As the fired bullet begins to drop, the angle of attack through the air changes, which provides lift to the bullet. A bullet simply dropped through air acquires no lift, only the drag due to its downward fall. In another example, a bullet fired from a non-rifled gun will not spin or acquire the gyroscopic stability, and so, the aerodynamic forces may cause the bullet to turn downward, point first, in which case, it will present a smaller cross-sectional area, which will cause it to fall faster than the dropped bullet that is "keyholing" its way through the air. There are many factors at play here. I have only mentioned a few.
11. ## The Secrets of Stealth

Jduff, I suppose you mean well, and I rarely deconstruct someone's post, but just about everything you say here doesn't make sense. Radio signature. Talking about "radio and or thermonic [sic] signatures" doesn't make sense. I'm sure you mean "radar signal". The term "thermonic signature" doesn't make sense. The word "signature" used with radio or thermonic in this manner doesn't make sense. Thermonic. By "thermonic", which is not a real word, I think you mean "thermionic"; however, I don't know of any remote sensing device that uses thermionics ... that is, a remote sensing device that emits particles. If you meant "thermal signature", then that's what the engine exhaust emits, which does not involve reflections on the aircraft's structural angles. Structural angles. Structural angles in stealth aircraft reflect incoming radar signals in directions other than back to the radar antenna, which anticipates receiving a reflection. Right-angled structures reflect signals back to their sources in the same way that a ball thrown into a right angle formed by a wall and the floor/ground returns to the thrower. See the diagram below. The right angle acts like a flat surface perpendicular to a radar signal regardless of the antenna's direction. So, stealth technology tries to avoid flat surfaces making right angles. Coatings. It is not obvious that a stealth aircraft would use reflective coatings; just the opposite, so this statement doesn't make sense. And it's not obvious that the coating should be silica. You also use the term "thermonic dispensation", which doesn't make any sense at all. And you mention electric current and electric charge, which also don't make sense. Invisibility. You mention that the two coatings on stealth aircraft make them nearly invisible, which is not only incorrect, but the photo you provide shows a very visible aircraft. And even if you meant that the carbon coating keeps heat to a minimum (instead of a "minimal"), this also doesn't make sense. Engines. The description of "a 90 degree angle towards the bottom of the craft" doesn't make sense. You mention "a honeycomb or a buckminsterfullerine [sic] shape". Honeycomb is a flat, and buckminsterfullerene is spherical, so this doesn't make sense. The idea of the "dampener" causing the heat to rise so that it does not escape from the aircraft doesn't make sense. I hope I'm wrong, but I don't know that you've provided anything useful here.
12. ## PLS HELP WITH THIS

So, first of all, they want a velocity-time graph. The first part involves acceleration and time, so what's the equation that relates velocity and acceleration and time? The uniform-velocity-and-time part should be fairly obvious by itself. The last part involving uniform retardation (braking) sounds similar to the first part. Try solving each part, and get back to us.
13. ## Starting a siphon ?

Explore it as Jacques Cousteau did (and others continue to do) at the Fontaine de Vaucluse in southern France, whose operation, I believe, continues to remain a mystery.
14. ## Syria Operation Farce

I think what iritates most Americans (and others) is that Obama is labeling a little pissant dictator halfway around the world a danger to America. A well-known quote — Accredited to a particular field marshal from 20th century Europe. And there's nothing clumsier than a Democrat trying to wage war, as Kennedy (Bay of Pigs) and Johnson (escalating Vietnam) proved.
15. ## Syria Operation Farce

Obama, a military amateur, probably didn't have contingency plans before setting a red line regarding/requiring military action. I don't see how he has the authority to engage in military action without Congress's approval, and even with Congress's blessings, it would be short-sighted to go it alone without several significant allies. France, although surprisingly on our side, doesn't count for much. Someone once said that going to war without France is like going deer hunting without an accordion. So true. Obama needs Congress and plenty of allies.

The square of the largest number is the sum of the squares of the other numbers 45 less than (x+2)² = x² + (x+1)² – 45 (x+2)² = x² + (x+1)² – 45
17. ## maths

I hope this is all tongue in cheek, otherwise we'd want them to stop saying "whilst" where merely "while" would suffice, and then there's all those instances of "ou" (eg, "colour") where merely an "o" would suffice (eg, "color"). They can't even spell "offense" and "defense", so it's no wonder they would have lost WW2 without our help (and they don't even say "World War Two", they say "the Second World War". C'mon people, no wonder they were losing!). Don't they realize (or "realise" — because they confuse their z's and s's) that WE won it? And who gave them permission to use "lorry" instead of "truck"? They also stress lots of wrong syllables, as when saying "weekEND" and "prinCESS". Blimey (or is that "Crikey"), who taught the English to speak English?? As someone famous once said, two countries divided by a common language.
18. ## SNAKES!!!!!

What may freak people out is their ability to "swim" on land (a unique/perplexing form of land locomotion), to have a vague end/tail when not fully exposed (aka, where is the end of its body?), to have a body much longer than its coils/sinusoids would suggest, to stop dead in its tracks (as it were), and to "vanish" while stock still if you look away and then try to find it again (aka "snake in the grass" ... or has it slithered away?). Or (E) All of the above.
19. ## Sulphuric Acid / King of Compounds

Sulfuric acid: Pumping up the volume tells of the history of sulfuric acid production and uses. It begins — A nice page on the topic.
20. ## Does echolocation produce an actual 'visible' image like in the movies?

In the real world, there is no color, only frequency. We've all seen "false color" images, right? What we need to keep in mind is that our human vision sees in "false color". For example, the two vote buttons on every post here are colored green and red. But what we perceive as green and red are not green and red — these colors (and the millions of other "colors" that we can "see") are synthetic "visual" characteristics created by our brains of particular ranges within the electromagnetic spectrum. And, if I remember correctly, we probably don't "see" (perceive) the actual light intensity, but instead, the log of the intensity. So, when the OP asks whether echolocation produces a "visual" image (of any kind), well, they're actually asking if it produces the images that we've come to know as our very much falsified/distorted visual perception of reality.
21. ## X and Y Chromosomes and Identity

Offhand, I don't know where to find what I wrote below on the Internet. When looking at achievement in general, I have read that, in comparison to females, males have relatively more "failures" (low IQ, learning disabilities, ADHD, autism, etc), but they also have more "successes" (high IQ, inventions, discoveries, etc). The idea is that, if you view each gender's achievement as a bell curve, the males' bell curve is more spread out (that is a larger sigma), and the female's bell curve is tighter. The idea being that Nature plays it safe with females, while allowing males to be more of a wild card. If I'm remembering this correctly, this theory posits that this phenomenon supposedly stems from females having two X chromosomes and males having only one. If there's a significant genetic mutation in one of the genes on one of the X chromosomes, the female can usually rely on the other X chromosome to provide a tried-and-true copy of it, but the male does not have this redundancy, and so, the consequences of that genetic mutation will express itself in the male, for better or worse. So, from this perspective, males are not inferior, but instead, they are the "test platform" for the one X chromosome that they carry, and so, males are instrumental in the advancement of the species (or at least our X chromosome). I don't know how true this is, but it makes a lot of sense to me. On the other hand, I can't agree about the extinction of men supposedly because the Y cannot repair itself. Maybe one male's lineage will go extinct due to his faulty Y chromosome, but there's plenty of other males with perfectly healthy Y chromosomes — and perhaps/probably there's a man out there somewhere with an enhanced Y chromosome. And, here's an article on the theory that the male Y chromosome might be evolving the fastest.
22. ## Cognitive load of being religious and scientific

I'm sorry to everyone. I'm surprised because I didn't think that I was diverging from the topic. I rarely get my hand slapped. My dictionary says the word religious "stresses faith in a particular religion and constant adherence to its tenets" (a direct quote from my Webster's New World Dictionary & Thesaurus, copyright 2005, Wiley Publishing Inc ... and Wiley also happens to be a well-known publisher of science). I choose not to stress my particular faith. I don't want to proselytize in this forum, and I don't want to give the appearance of doing so. Anyway, redacted more verbatim-ishly ... I am both religious and scientifically-minded, and I am not aware of me experiencing any cognitive load burden in day-to-day life, and I am not aware of me switching back and forth between religious situations and "scientific" situations. I mean that my religion is always with me, and my scientific mind is always with me, and there's no conflict between the two. Perhaps if icehorse could give an example(s) or go into further detail, I could explain myself further.
23. ## Cognitive load of being religious and scientific

My recognition/acceptance that I exist spiritually does not prevent me from functioning in the physical world as well as anyone else.
24. ## X and Y Chromosomes and Identity

You're right. The mother has two X chromosomes; recombination (ie, mixing) can/does occur, and she passes down a recombined X chromosome (that's almost guaranteed to be different for every egg) to all her offspring. The father has one X and one Y chromosome; recombination cannot occur between them. He can only pass down his X chromosome to his daughter-to-be just as he received it from his mother, and he can only pass down his Y chromosome to his son-to-be just as he received it from his father. These videos explain this (and more) very well, and all of them are worth watching, There's also the correlation between surnames and Y chromosomes due to both being "inherited" from only the father. (But if mom "jumps the fence", then all bets are off.)
25. ## Pi as a circle's circumference integrated using two points and a right triangle

I got to thinking about this from two recent threads on the nature of pi. We're all familiar with scribing a semi-circle using two points (A and C) and a right triangle, shown below. How then would the distance along the circumference of the semi-circle be computed using integration? Can it be done without using trigonometry, or is trig inherently part of the process? Pi would then be the ratio of the semi-circle's circumference to ½ of AC. I apologize for not thinking this out myself, but I haven't focused in this mathematical direction in quite some time.
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