Answerbag: xprofessor's answers

Answer to Do you believe you're intelligently designed? or you're a random product of near-misses and incidental changes over a long period of time?

Thu, 17 May 2012 10:52:54 -0700

Do you believe you're intelligently designed? or you're a random product of near-misses and incidental changes over a long period of time?

Natural selection over billions of years gives the *illusion* of design, even though there is no designer.

Answer to Let's say your body dies today and your thought live remains. Where will you go?

Fri, 04 May 2012 11:06:10 -0700

Let's say your body dies today and your thought live remains. Where will you go?

No evidence for mind-body duality. Your mind is your brain. When the brain dies, your mind & your "personhood" dies as well. Nothing persists. "When you're dead, you're dead."

Answer to If your nails are dead how do they grow?

Fri, 27 Apr 2012 20:49:02 -0700

If your nails are dead how do they grow?

The nail is pushed forward by living tissue at the nail's base -- works the same way for hair & hair follicles.

Answer to i have not smoked in 5 months, i smoked a blunt lastnight. i have a urin drug test in 18 days i weight 200 lbs will i be clean by then?

Sat, 21 Apr 2012 13:58:07 -0700

i have not smoked in 5 months, i smoked a blunt lastnight. i have a urin drug test in 18 days i weight 200 lbs will i be clean by then?

Probably you'll be ok, assuming the usual threshold of 50 ng/dl. You'll find a lot of misinformation and worthless "folk remedies" for passing the test, but not much you can do about it, except maybe drink lots of water the day of testing to dilute the urine specimen. Forced diuresis (causing...

Answer to If the statement S → t,T → U are truethen what statement is logically equivalen, mulitple choice in description

Tue, 17 Apr 2012 06:50:49 -0700

If the statement S → t,T → U are truethen what statement is logically equivalen, mulitple choice in description

I'm assuming that t and T represent the same proposition in your question. Also that T stands for a proposition and not the truth tautology. So if S --> T and T --> U then, from transitivity of implication, it follows that S --> U, i.e., that S implies U. But if a statement is true then...

Answer to Someones dealt 2 cards from a deck of 52 cards whats the probability they receive a blackjack

Thu, 29 Mar 2012 09:45:39 -0700

Someones dealt 2 cards from a deck of 52 cards whats the probability they receive a blackjack

Oops -- my final answer should be 4.8264% - about one in 21, nowhere close to 50%. Darn decimal point...

Answer to Someones dealt 2 cards from a deck of 52 cards whats the probability they receive a blackjack

Wed, 28 Mar 2012 22:43:30 -0700

Someones dealt 2 cards from a deck of 52 cards whats the probability they receive a blackjack

A blackjack consists of an ace paired with either a 10, J, Q, or K. There are 4 aces in the deck and 16 cards ranked 10-K. The probability of dealing an ace first is 4/52. The probability of next dealing10-K is 16/51. The probability of both of these occurring is the product (4/52)*(16/51) =...

Answer to Do you know anyone who appears to be the missing link?

Sun, 25 Mar 2012 14:58:25 -0700

Do you know anyone who appears to be the missing link?

My brother-in-law.

Answer to Why did God create animals?

Thu, 08 Mar 2012 11:00:38 -0800

Why did God create animals?

This is a science forum. In science we seek naturalistic explanations for the physical world and philosophically don't recognize anything supernatural, such as deities. Your question is loaded with an assumption, "God created animals", that is not recognized in science. In the view of...

Answer to Fatorise this equation x^4-16

Thu, 08 Mar 2012 10:43:52 -0800

Fatorise this equation x^4-16

For some reason I can't see all previous answers, so sorry if duplication... I presume you mean factorise this *expression* as it's not an equation and you don't factor equations. It has the form of DIFFERENCE OF SQUARES a^2 - b^2 - (a+b)(a-b) (Learn this formula) Also note x^4 = (x^2)^2...

Answer to what makes the earth spin on its axis

Tue, 06 Mar 2012 16:44:31 -0800

what makes the earth spin on its axis

Angular momentum is a conserved quantity. So the present-day spinning is left over from the Earth's formation from a swirling cloud of dust & gas. It's always been spinning.

Answer to Do theoretical physicists have any evidence for their theories? Why should we believe anything they say?

Sun, 26 Feb 2012 13:50:17 -0800

Do theoretical physicists have any evidence for their theories? Why should we believe anything they say?

Certainly. Otherwise it's mere speculation or hypothesis. The purpose of scientific theory (in the strict scientific sense) is to broadly explain many physical observations using the simplest possible assumptions. The big bang theory of cosmology, for example, explains the cosmic microwave...

Answer to Extending trigonometry question. Pleas help?!?!

Sun, 22 Jan 2012 16:13:17 -0800

Extending trigonometry question. Pleas help?!?!

Hint: (5,12,13) is a Pythagorean triple, i.e., the sides of a right triangle. 5^2 = 25 12^2 = 144 13^2 = 169 25 + 144 = 169

Answer to In the anatomical position your thumb is______________?

Thu, 19 Jan 2012 13:33:12 -0800

In the anatomical position your thumb is______________?

toward the outside of the body (palms facing forward)

Answer to If a guy you didn't like was hiding from a swarm of bees, would you point to his hiding place hoping the bees would find him?

Fri, 13 Jan 2012 13:42:27 -0800

If a guy you didn't like was hiding from a swarm of bees, would you point to his hiding place hoping the bees would find him?

Bees don't read human body language and have no idea that you are "pointing" at something.

Answer to How the bloody hell do i solve equations ...

Thu, 10 Nov 2011 10:41:27 -0800

How the bloody hell do i solve equations ...

The trick is to figure out how to isolate the variable so you end up with something like "x = ..."

Answer to Can the sine or the cosine function ever equal 5?

Thu, 10 Nov 2011 10:34:16 -0800

Can the sine or the cosine function ever equal 5?

No. Sine and cosine values are limited to the range +1 (max) to -1 (min). Picture coordinates of points on a unit circle. This is a very basic concept that you should completely understand.

Answer to Is it a sin to masturbate alone?

Sun, 06 Nov 2011 15:41:03 -0800

Is it a sin to masturbate alone?

cosin, not sin

Answer to How many seconds are in a third?

Sun, 30 Oct 2011 21:26:55 -0700

How many seconds are in a third?

If by "seconds" you mean "halves", then the answer is (1/3) / (1/2) = 2/3. There are 2/3 of one-half in one-third. While we use ordinal numbers to indicate fractional denominators (thirds, fourths, fifths, etc.), the fraction 1/2 is referred to as a "half" and not a "second."

Answer to how do we add irrational numbers?

Tue, 11 Oct 2011 07:33:15 -0700

how do we add irrational numbers?

Addition is well-defined for all real numbers. It's just that irrationals can't be expressed as simple decimals or fractions (they have an infinitely long non-repeating series of decimal digits) so their sum might not have a simple notation the way rational numbers do. For example, we can...

Answer to An Helium balloon ......... read below

Fri, 16 Sep 2011 23:16:49 -0700

An Helium balloon ......... read below

Here's how I'd approach it. 1) Buoyancy is related to the difference in densities. The densities of air and helium at 1 Atmosphere can be obtained. Their difference creates the buoyancy. A mass of 85 Kg (about 187 pounds) divided by the difference in densities between air and helium will give...

Answer to Does anyone know the specs on the telescope used by Copernicus to view Jupiter and its moons? Lens size, length, etc.

Sat, 10 Sep 2011 20:55:13 -0700

Does anyone know the specs on the telescope used by Copernicus to view Jupiter and its moons? Lens size, length, etc.

A typical Galilean telescope with which Jupiter's moons could be observed was configured as follows. It had a plano-convex objective (the lens toward the object) with a focal length of about 30-40 inches., and a plano-concave ocular with a focal length of about 2 inches....

Answer to Why is anything raised to the power of zere equal to one?

Tue, 06 Sep 2011 21:26:51 -0700

Why is anything raised to the power of zere equal to one?

Power tells you how many times the base number is used as a factor for multiplying. For example, a number raised to the 5th power indicates that it appears five times as a factor. When you multiply you can always insert additional factors of 1, since multiplying by 1 does not change the value....

Answer to When your time is up how do you get it down?

Mon, 29 Aug 2011 14:03:50 -0700

When your time is up how do you get it down?

You take "down time."

Answer to Explain to me how an object of large mass, say, the Earth, creates gravity. Why does the smaller object orbit the larger object?

Thu, 25 Aug 2011 20:40:29 -0700

Explain to me how an object of large mass, say, the Earth, creates gravity. Why does the smaller object orbit the larger object?

The smaller object doesn't actually orbit the larger -- they both orbit their common center of mass. Two equally massive bodies will orbit a point midway between them. If one body is much heavier than the other, however, then the center of mass will be close to the heavier body's center. Thus the...

Answer to What is the four color theorem?

Sat, 13 Aug 2011 09:29:11 -0700

What is the four color theorem?

Four colors suffices (you don't need more than 4) to color any map so that adjacent regions (sharing a common boundary) are all different colors. It was an unproven conjecture until the 1970s, when it was "proven" by a computer program -- still some controversy about the proof.

Answer to The components of DNA have been confirmed to exist in meteorites, researchers stated. Does that mean we are all extraterrestrials?

Thu, 11 Aug 2011 19:23:17 -0700

The components of DNA have been confirmed to exist in meteorites, researchers stated. Does that mean we are all extraterrestrials?

Actually what they found were molecular components of DNA -- still pretty amazing. I don't think this finding supports the panspermia hypothesis over local abiogenesis. What it suggests, however, is that DNA might not be as exotic as we think. Thursday, Aug. 11, 2011...

Answer to Since all science is inductive (based on limited observation of patterns), to what extent does science prove anything? Are all scientific conclusions ultimately reducible to theoretical speculation? If so, how can we ever speak of causes in nature?

Thu, 11 Aug 2011 11:04:30 -0700

Since all science is inductive (based on limited observation of patterns), to what extent does science prove anything? Are all scientific conclusions ultimately reducible to theoretical speculation? If so, how can we ever speak of causes in nature?

"All science is inductive." Not so. The scientific method combines physical observation with DEDUCTIVE reasoning, allowing facts and laws to be established with high levels of confidence ("proof"). The INDUCTIVE part comes into play when formulating new hypotheses, i.e., making educated guesses...

Answer to Why earth rotates from west to east & why not from east to west?

Thu, 11 Aug 2011 10:44:40 -0700

Why earth rotates from west to east & why not from east to west?

Think in terms of angular momentum. The vast cloud of dust and gas, from which the solar system formed, had some net angular momentum -- an axis around which there was net rotational motion of all the particles. It's no coincidence, then, that Earth orbits the sun in the same rotational sense...

Answer to Did the big bang actualy happen?

Mon, 08 Aug 2011 10:00:57 -0700

Did the big bang actualy happen?

Big bang cosmology rests on three solid pillars of evidence. First is the uniform expansion of the universe according to Hubble's law, discovered in the 1920s, where objects are rushing away from each other at a speed proportional to their distance. Second is cosmic microwave background...

Answer to What theorem would I have to apply to a quadrilateral inside a semicircle?

Sun, 07 Aug 2011 11:34:52 -0700

What theorem would I have to apply to a quadrilateral inside a semicircle?

Angles in the same segment are equal.

Answer to Do you think humans will ever discover an afterlife?

Sat, 06 Aug 2011 10:12:21 -0700

Do you think humans will ever discover an afterlife?

No. When you die the brain disintegrates. Everything that is your mind, your memories, your "personhood" ceases to exist within 5 to 10 minutes. It's a one-way process than cannot be undone any more than unbreaking an egg. Afterlife is a comfortable fiction by which people avoid confronting the...

Answer to Is it wrong if i like school but my favorite subject is math?

Tue, 02 Aug 2011 12:51:08 -0700

Is it wrong if i like school but my favorite subject is math?

I liked school and math was my favorite subject, too. Strength in math represents ability at abstract reasoning and and analytical view of things -- qualities that will be very useful no matter what your chosen career.

Answer to THE software installer has 4 letter identification codes. if each letter can be used only once, how many diff. ways can it be arranged?

Sun, 31 Jul 2011 14:20:16 -0700

THE software installer has 4 letter identification codes. if each letter can be used only once, how many diff. ways can it be arranged?

Assuming there are 26 letters to choose from initially, the total number is 26*25*24*23

Answer to 16000psi is needed bend a metal beam, how fast would i have to drive a 4tonne truck into it before it bends?

Mon, 25 Jul 2011 11:50:29 -0700

16000psi is needed bend a metal beam, how fast would i have to drive a 4tonne truck into it before it bends?

I don't think there's enough information. It's like asking how high a bathroom scale will momentary read if a 150-pound man jumps on it from a certain height? It depends on time-dependent details of the collision that are not given.

Answer to You enter a competition with 100 contestants so have a 1% chance of winning. You repeat the same competition. Would your chance then be 2%?

Sat, 23 Jul 2011 20:43:25 -0700

You enter a competition with 100 contestants so have a 1% chance of winning. You repeat the same competition. Would your chance then be 2%?

It would be roughly, but not quite, 2% after two tries. I'll assume that if you win the first competition there's no point in repeating it. So your total chance of winning is 1/100 + (99/100)(1/100) = 0.0199 = 1.99%. Another way of looking at it is that your chance of losing either round is...

Answer to Do animals go to "heaven" or "hell" when they die, or have any afterlife?

Sat, 16 Jul 2011 13:19:07 -0700

Do animals go to "heaven" or "hell" when they die, or have any afterlife?

Science has no answer to this question. It is a religious / metaphysical issue beyond the reach of observable physical evidence.

Answer to what is the answer to this problem? 2a5 + c2 if a = 2 and c = 4

Mon, 11 Jul 2011 19:06:16 -0700

what is the answer to this problem? 2a5 + c2 if a = 2 and c = 4

It might mean that if a=2 then 2a5 = 225 and if c=4 then c2 = 42. Just substituting symbols for digits as in cryptarithm puzzles. Not really algebra. In that case the answer would be 225 + 42 = 267.

Answer to What positive fraction smaller than 1 is equal to itself when inverted?

Sun, 10 Jul 2011 12:16:29 -0700

What positive fraction smaller than 1 is equal to itself when inverted?

For all real numbers a (except 0) if |a| less than 1 then |1/a| greater than 1. [Using "absolute value" function; for some reason the 'greater than' and 'less than' symbols get messed up here.] If a is positive as well then 1/a isn't smaller than a in either sense of "smaller" (more to the left...

Answer to for the mathematicians out there: (2n+m)/3=integer (n,m integers) does it follow that (2m+n)/3=integer ?

Sat, 09 Jul 2011 10:35:31 -0700

for the mathematicians out there: (2n+m)/3=integer (n,m integers) does it follow that (2m+n)/3=integer ?

Yes, it follows. This involves congruence relations in modular arithmetic. If x/3 is an integer, then we say x is congruent to 0 modulo 3: x == 0 (mod 3) (using == to represent the triple equals sign ≡ normally used for congruence) We are given 2n+m == 0 (mod 3) for integers n and m...

Answer to why do farts smell like ass

Thu, 07 Jul 2011 18:05:57 -0700

why do farts smell like ass

The smell comes from the same source: intestinal microbes that release noxious gases as they metabolize substrate in feces.

Answer to When twins are born, what measures are taken in the hospital to ensure they don't get muddled up?

Sat, 02 Jul 2011 11:34:25 -0700

When twins are born, what measures are taken in the hospital to ensure they don't get muddled up?

ID bands are applied to the wrist or ankle in the delivery room shortly after birth. Initially they are identified as A (first born) and B (second born). The 3rd triplet is C, and so on.

Answer to Is any company in the world today developing a supercomputer that is the most closest thing to a self-aware Artificial Intelligence (A.I.)?

Fri, 24 Jun 2011 10:10:17 -0700

Is any company in the world today developing a supercomputer that is the most closest thing to a self-aware Artificial Intelligence (A.I.)?

Nobody knows how, even in principle. We don't even understand HUMAN self-awareness!

Answer to Someone please help me for the geometry regents: How do I prove a rhombus is not a square?

Tue, 21 Jun 2011 15:31:12 -0700

Someone please help me for the geometry regents: How do I prove a rhombus is not a square?

You can't prove it -- it follows purely from the definitions of terms "rhombus" and "square," and is not really a theorem to be proven. A square is a kind of rhombus, i.e., some rhombuses are not squares because they don't have right angles. (Somewhat off-topic, a square is also a kind of...

Answer to how is it possible that the sum of a infinite series add up to a finite value? it doesn't make sense intuitively.

Fri, 17 Jun 2011 17:03:18 -0700

how is it possible that the sum of a infinite series add up to a finite value? it doesn't make sense intuitively.

Your confusion was shared by the great thinkers of antiquity like Zeno of Elea. One of his famous paradoxes notes that to move from one place to another, an object must first cover half the distance to its destination. Then it must cover half the remaining distance, and so on. There are an...

Answer to How do you find the center of 2 concentric circles by using 2 parallel lines and a ruler?

Thu, 16 Jun 2011 15:38:44 -0700

How do you find the center of 2 concentric circles by using 2 parallel lines and a ruler?

Given two concentric circles, all you need to find their center is a straightedge and compass. Any line tangent to the inner circle will intersect the outer circle at two points. Construct the perpendicular bisector line between these points (a well-known procedure). Then repeat the above using a...

Answer to Why is this calculation correct?:D 102 + 22 = 201

Mon, 13 Jun 2011 13:02:05 -0700

Why is this calculation correct?:D 102 + 22 = 201

With digits 0, 1, and 2 you are using base-3. So the digits represent (right to left) 1s, 3s, 9s, 27s, 81s, etc -- the powers of 3. Hence 102 (base 3) = 1*9 + 0*3 + 2 (decimal) = 11 (dec) 22 (base 3) = 2*3 + 2 = 8 (dec) 11 + 8 (dec) = 19 (dec) = 2*9 + 0*3 + 1 = 201 (base 3) You could line them...

Answer to Do you know HOW to use a slide-rule and/or an Abacus? If so, DO you use one? Why?

Sat, 11 Jun 2011 14:23:55 -0700

Do you know HOW to use a slide-rule and/or an Abacus? If so, DO you use one? Why?

They didn't invent hand-held calculators until around 1972, after finishing all my math and physics studies. I had a Post Versalog "professional" slide rule that routinely gave 3 significant figures but often 4 sig figs using log-log scales. You had to figure order of magnitude in your head. ...

Answer to If f(x)=x^2-2x+1 and g(x)=x-1 what is (f/g)(x) please help fast. =/

Thu, 09 Jun 2011 09:28:47 -0700

If f(x)=x^2-2x+1 and g(x)=x-1 what is (f/g)(x) please help fast. =/

Just remember that f/g is undefined at x=1

Answer to How many systems of mathematical induction can you count quickly? Examples: 1 2 3...4 16 256....

Fri, 03 Jun 2011 12:24:52 -0700

How many systems of mathematical induction can you count quickly? Examples: 1 2 3...4 16 256....

Online Encyclopedia of Integer Sequences: http://oeis.org/

Answer to How many times should the average healthy human being poop?

Thu, 02 Jun 2011 21:08:57 -0700

How many times should the average healthy human being poop?

Every 2 or 3 days for a bowel movement is normal, assuming well-formed stools, eating a normal diet with no indigestion. There are people who poop every day or more, but it's not required for health. Notwithstanding many false claims to the contrary... The GI tract seems to set its own speed and...

Answer to The two segments tangent to a circle from a point outside the circle are congruent. Why?

Tue, 31 May 2011 13:45:04 -0700

The two segments tangent to a circle from a point outside the circle are congruent. Why?

Two lines tangent to a circle at opposite points (connected by a diamter, making a 180-degree arc between them on the circle. They intersect "at infinity" making an angle of zero. As the intersection point moves closer to the circle, the tangents intersect at some angle & subtend a smaller...

Answer to If x is the geometric mean between q and r, solve x in terms of q and r.

Wed, 25 May 2011 22:06:47 -0700

If x is the geometric mean between q and r, solve x in terms of q and r.

x = sqrt(q*r) where sqrt means square root and * means multiplication. You really aren't solving for x -- more like defining it.

Answer to what is the pharynx also called

Wed, 25 May 2011 20:37:11 -0700

what is the pharynx also called

throat

Answer to How is gas formed in the gut?

Sun, 22 May 2011 23:03:41 -0700

How is gas formed in the gut?

It's a metabolic waste product of the massive bacterial flora in the gut. 90% of the dry mass of feces is bacteria, and they virtually all produce gas.

Answer to How many degrees are in a kelvin?

Sun, 15 May 2011 22:30:04 -0700

How many degrees are in a kelvin?

One kelvin = one degree on the Kelvin temperature scale. This is the same size as one degree Celsius, i.e., they both measure the same difference in temperature, though differ greatly in the location of zero. One kelvin is also 5/9 of one degree Fahrenheit.

Answer to What does the word"halogen"mean?

Sat, 07 May 2011 08:16:40 -0700

What does the word"halogen"mean?

Literally, "salt former" (halo- = salt; -gen = formation)

Answer to why arent the pulmonary cirucuit and lungs operative in the fetus

Thu, 05 May 2011 14:49:45 -0700

why arent the pulmonary cirucuit and lungs operative in the fetus

Fetuses don't breathe. They obtain oxygen from the maternal circulation.

Answer to Is there a scientific basis for race?

Tue, 26 Apr 2011 09:32:20 -0700

Is there a scientific basis for race?

No. Obvious phenotypic differences among populations of humans (i.e., skin color, facial features, etc.) are just that -- phenotypical variation from a few genes out of tens of thousands that distinguish each individual. Genetically there's no more variation between so-called races than there is...

Answer to Can someone please explain what exactly an EVP is?

Tue, 26 Apr 2011 09:07:24 -0700

Can someone please explain what exactly an EVP is?

Auditory pareidolia. It's a form of hallucination, where you perceive something that isn't really there. It's what our human brains -- which excel at finding patterns from noise -- do when presented with random input. The claim that it represents something real (e.g., ghosts) is hilariously...

Answer to If a one-sided person undresses, is it a Mobius strip?

Sun, 24 Apr 2011 10:25:49 -0700

If a one-sided person undresses, is it a Mobius strip?

...only to music by a Mobius band.

Answer to In science and technology what is something good to start looking into?? (to research and learn about)

Fri, 22 Apr 2011 11:04:22 -0700

In science and technology what is something good to start looking into?? (to research and learn about)

This is an exciting time in molecular biology -- we are starting to bridge the gap between microscopic and atomic. Protein structure (folding, unfolding, non-folding) is undergoing exciting new insights. Evo-devo is also still a hot topic -- research in how animals develop from eggs.

Answer to The sum of first 10 odd numbers is 100, find any five numbers from those(First 10 odd numbers) whose sum is 50?

Sat, 09 Apr 2011 14:41:08 -0700

The sum of first 10 odd numbers is 100, find any five numbers from those(First 10 odd numbers) whose sum is 50?

WHLB is right. It's asking to find 5 odd numbers whose sum is 50. Of note, however, is that the series obtained by adding successive odd numbers forms the squares of the integers: 1 = 1 4 = 1 + 3 9 = 1 + 3 + 5 16 = 1 + 3 + 5 + 7 etc. In general the sum of the first k odd numbers (1 + 3 +...2k-1)...

Answer to What makes peppers taste hot?

Sat, 09 Apr 2011 08:01:49 -0700

What makes peppers taste hot?

Capsaicin, the main active ingredient in peppers, stimulates the same receptor molecules in the mouth and lips that are normally activated by heat or abrasion. Hence the burning sensation.

Answer to Is overpopulation a big problem that has yet to be discussed?

Tue, 05 Apr 2011 12:14:45 -0700

Is overpopulation a big problem that has yet to be discussed?

Share your answer...

Answer to Prove that the sum of the roots of a polynomial of degree n is -B/A

Tue, 29 Mar 2011 13:57:36 -0700

Prove that the sum of the roots of a polynomial of degree n is -B/A

Hey @WarHorseLeBron, take a look at this discussion of sums and products of roots of polynomials...from MathForum.org ("Ask Dr. Math"): http://mathforum.org/library/drmath/view/61024.html

Answer to what is the square root of x squared

Fri, 25 Mar 2011 18:56:42 -0700

what is the square root of x squared

The question is ambiguous. The square root of (x^2) = |x| = absolute value of x. The (square root of x)^2, on the other hand, equals x if x non-negative and undefined if x is negative.

Answer to if adam can build a fence in 2 hours and sam can build the same fence in 6 hours how long would it take for both of them to build it

Wed, 23 Mar 2011 20:08:54 -0700

if adam can build a fence in 2 hours and sam can build the same fence in 6 hours how long would it take for both of them to build it

In this kind of problem, you have to figure the *rates* of fence building measured in fences per hour (fph). When both guys are working, their rates of work add together. But rate and time are inversely related. Adam builds 1 fence in 2 hours = 0.5 fph. Sam build 1 fence per 6 hrs = 0.167 fph....

Answer to What does an e at the end of a number mean?

Tue, 22 Mar 2011 12:06:19 -0700

What does an e at the end of a number mean?

...unless you mean something like "1.23E+12" That's an expression of scientific notation, meaning "1.23 times 10 raised to the 12th power"

Answer to What is 1 plus 1?

Mon, 21 Mar 2011 18:17:47 -0700

What is 1 plus 1?

1 plus 1 is 10 in binary. While 1 and 1 is 1.

Answer to With all our experience with nuclear plants, why haven't we better protective suits against radiation?

Mon, 21 Mar 2011 12:12:20 -0700

With all our experience with nuclear plants, why haven't we better protective suits against radiation?

The high-energy particles typical of radioactivity can penetrate just about any thin material including lead. Make shielding heavier and they're no longer just "suits" you can just walk around in.

Answer to Please help with this probability question

Sun, 20 Mar 2011 17:49:20 -0700

Please help with this probability question

There are 8 students to begin with, so the probability pGirl = 5/8 and pBoy = 3/8. Consider all 4 situations: GG, GB, BG, BB where G & B stand for girl & boy. p(GG) = (5/8)*(4/7) Comment: 4/7 = 4 remaining girls out of 7 remaining students. = 20/56 = 5/14 = 0.357 pGB = (5/8)*(3/7)...

Answer to What long term benefits does natural male enhancement (creams, pills) give you?

Wed, 16 Mar 2011 23:08:14 -0700

What long term benefits does natural male enhancement (creams, pills) give you?

None. Also no short-term benefits. The vendors benefit from your payments.

Answer to Other than a static one, what were you doing the last time you got an electrical shock?

Mon, 14 Mar 2011 08:22:07 -0700

Other than a static one, what were you doing the last time you got an electrical shock?

I was changing a pair of electrical switches ganged together in the same box. I had turned off the circuit breaker so the light went out. Much to my surprise the *other* switch was on a different circuit so it was still hot. Whoa! The worst shock was when I was a kid, standing on a concrete...

Answer to Why do people now think that the big bang is a fact not a theory?

Sun, 13 Mar 2011 13:34:24 -0700

Why do people now think that the big bang is a fact not a theory?

Big bang cosmology rests on three major lines of evidence: (1) Hubble's Law -- the uniform expansion of the universe; (2) the relative abundances of hydrogen & helium, where there is excellent agreement between theory and observation; (3) the cosmic microwave background radiation (CMB), aka...

Answer to Why do people now think that the big bang is a fact not a theory?

Sun, 13 Mar 2011 13:28:16 -0700

Why do people now think that the big bang is a fact not a theory?

Share your answer...

Answer to What is the rule from x to y?

Sun, 13 Mar 2011 11:20:30 -0700

What is the rule from x to y?

Triangular numbers -- http://mathworld.wolfram.com/TriangularNumber.html y = x(x+1)/2 Note than y = 1 + 2 + 3 + ... x

Answer to Find x in the rectangle?

Fri, 11 Mar 2011 17:02:11 -0800

Find x in the rectangle?

I can't the image to load, but based on other images posted above, it looks like you use the fact that the bottom triangle with the 15 degree angle is isosceles (based on the symmetry of a rectangle), so the triangle has two 15-degree angles, making the vertex angle 180 - (15+15) = 150 degrees....

Answer to Why cant we predict earthquakes accurately?

Sat, 05 Mar 2011 14:55:16 -0800

Why cant we predict earthquakes accurately?

Continental plates slide sideways at earthquake fault zones. They stick together for a long time, building up huge forces without moving, followed by an occasional sudden slippage that releases energy to cause an earthquake. Scientists have no way of knowing exactly when and where the force...

Answer to What are the steps to the scientific method?

Wed, 23 Feb 2011 02:41:54 -0800

What are the steps to the scientific method?

1. Study what is already known about the topic. 2. Use inductive reasoning to formulate a hypothesis. 3. Make observations according to some design. 4. Apply deductive reasoning to make sense of these observations. 5. Confirm or refute your hypothesis. This is probably not what they taught you,...

Answer to My professor told me that there is a perfect square under the radical here. sqrt(8+4e^(4t)+4e^(-4t)) Help a brother out? Show me how?

Mon, 21 Feb 2011 22:04:05 -0800

My professor told me that there is a perfect square under the radical here. sqrt(8+4e^(4t)+4e^(-4t)) Help a brother out? Show me how?

Start with the formula for a perfect square: (a+b)^2 = a^2 + 2a*b + b^2 If you set a = e^2t and b = e^-2t then a^2 = e^4t and b^2 = e^-4t while a*b = e^(2t)*e^(-2t) = e^0 = 1 So you see that [(e^(2t) + e^(-2t)]^2 = e^(4t) + 2 + e^(-4t) All that remains is to multiply the previous line by 4:...

Answer to Does a room get warmer faster by setting the thermostat at a higher temp and then lowering it once the desired temp is reached.

Mon, 21 Feb 2011 03:55:47 -0800

Does a room get warmer faster by setting the thermostat at a higher temp and then lowering it once the desired temp is reached.

Usually not, because most thermostats act merely as on-off switches -- they either call for heat or they don't, not affecting the rate of heating. The exception is in some systems that combine a heat pump with electric resistance heating, where the heat pump heats slowly for room temps a little...

Answer to Odds that A speaks truth are 3:2 and the odds that B does so are 5:3. In what percentage of cases are they likely to contradict each other?

Sun, 20 Feb 2011 10:39:39 -0800

Odds that A speaks truth are 3:2 and the odds that B does so are 5:3. In what percentage of cases are they likely to contradict each other?

First, convert from odds to probability (they're not the same thing). The probability (call it Pa) that A speaks the truth is 3/(3+2) = 3/5. Likewise Pb = 5/(5+3) = 5/8. So the probabilities of falsehood are 2/5 and 3/8, respectively. That is, 1-Pa and 1-Pb. For A and B to contradict each other...

Answer to a person's car traveled 60 miles in 45 minutes. How many miles per hour was it traveling?

Sat, 19 Feb 2011 08:34:41 -0800

a person's car traveled 60 miles in 45 minutes. How many miles per hour was it traveling?

The word "per" can be translated mathematically as "divided by." So 60 miles per 45 minutes is a speed of 60/45 miles per minute 60/45 -- divide numerator & denominator by 15 to get 4/3 miles per minute. 60 minutes = 1 hour (4/3 mi/min)(60 min/hr) = 240/3 = 80 miles per hour. Note that...

Answer to It was stated"the death of the host is a result as harmful to the virus's future as to that of the host itself." Explain the significance

Thu, 17 Feb 2011 15:23:25 -0800

It was stated"the death of the host is a result as harmful to the virus's future as to that of the host itself." Explain the significance

Viruses require host cells in which to replicate. If they kill their host then they can't continue replicating.

Answer to why do aniamlas smell after thay die?

Thu, 17 Feb 2011 15:21:58 -0800

why do aniamlas smell after thay die?

Micro-organisms (chiefly bacteria) begin consuming the animal -- both from the inside and from the outside. These generate smelly gases as by-products of their metabolism.

Answer to What is the significance of this equation: ΔMi−1 = −∂Σn=1NDi[n][Σj∈C{i}Fji[n − 1] + Fexti[[n−1]]

Thu, 10 Feb 2011 12:31:40 -0800

What is the significance of this equation: ΔMi−1 = −∂Σn=1NDi[n][Σj∈C{i}Fji[n − 1] + Fexti[[n−1]]

It looks like complete nonsense. The presence of a partial derivative symbol occurring only once, for instance, and preceding a sigma (summation) symbol, makes no sense mathematically or even syntactically. Somebody decided to go wild with mathematical typography. It's so meaningless as to be, as...

Answer to What is Zero times any number, X, where X is not equal to infinity.

Tue, 08 Feb 2011 16:57:46 -0800

What is Zero times any number, X, where X is not equal to infinity.

No need to qualify the number X as "not equal to infinity," because infinity is not a number. It's sufficient to state that any number times zero is zero.

Answer to Practice and practiced; however, I cannot solve for x, please help?

Sat, 05 Feb 2011 08:39:49 -0800

Practice and practiced; however, I cannot solve for x, please help?

Multiply both sides by 3: 4(x+2) = 3(3x-1) Expand: 4x + 8 = 9x - 3 Subtract 4x from both sides: 8 = (9x - 4x) - 3 8 = 5x - 3 Add 3 to both sides: 8 + 3 = 5x 11 = 5x Divide by 5: 11/5 = x

Answer to Out of 10 white, 9 black and 7 red balls, in how many ways can we select one or more balls

Fri, 04 Feb 2011 17:16:56 -0800

Out of 10 white, 9 black and 7 red balls, in how many ways can we select one or more balls

"One or more" is a tall order. For the first single ball selected: Total number of balls = 10 + 9 + 7 = 26 Probability of White: pWhite =10/26 = 5/13 pBlack = 9/26 pRed = 7/26 Selecting a second ball: Now have a total of nine 2-ball sequences: white-white white-black white red ... red-black...

Answer to A and B throw a dice. The probability that A's throw is not greater than B's is

Fri, 04 Feb 2011 16:59:53 -0800

A and B throw a dice. The probability that A's throw is not greater than B's is

I would enumerate (list) all 36 possible outcomes. 1-1, 1-2, ... 6-5, 6-6, where A-B represents their respective throws. Each of these 36 pairs is equally probable at 1/36. In some pairs it's true that "A is not greater than B" and in some pairs it's false. Count the trues. That's the numerator,...

Answer to The distance from the middle of a regular hexagon to the midpoint of a side is 15cm. Find the area of the regular hexagon.

Thu, 03 Feb 2011 19:50:57 -0800

The distance from the middle of a regular hexagon to the midpoint of a side is 15cm. Find the area of the regular hexagon.

The hexagon consists of 6 equilateral triangles. You are give an altitude of one of these triangles. Can you take it from there?

Answer to if the zeros at the end of a whole number may or may not be significant, explain why this is so and give a plentiful variety of examples

Wed, 02 Feb 2011 09:56:27 -0800

if the zeros at the end of a whole number may or may not be significant, explain why this is so and give a plentiful variety of examples

You need to understand the concepts of rounding and significant figures. Mathematically there's no difference between 500 and 500.00 Say I went to a concert and estimated there were 500 people present, just sort of eyeballing it. The true figure was probably closer to 500 than it was to 400 or...

Answer to how do you simplify x(x2 + x + 1) – x2 =

Tue, 25 Jan 2011 21:43:44 -0800

how do you simplify x(x2 + x + 1) – x2 =

Assuming that by x2 you mean x-squared = x^2... x (x^2 + x + 1) - x^2 = x^3 + x^2 + x - x^2 = x^3 + x = x (x^2 + 1)

Answer to the letter which best completes the sequence below is A D E H I

Tue, 25 Jan 2011 21:35:01 -0800

the letter which best completes the sequence below is A D E H I

L would come next, if the rule is drop two, write two, drop two, etc. A (b c) D E (f g) H I (j k) L M...

Answer to The square root of 934 lies between what two whole numbers?

Mon, 24 Jan 2011 16:08:01 -0800

The square root of 934 lies between what two whole numbers?

I assume you're supposed to estimate without resort to a calculator. You know that 30^2 = 900 so it has to be bigger than 30. Consider 31^2. This is (30 + 1)^2 Since (a+b)^2 = a^2 + 2ab + b^2, it follows that (30+1)^2 = 900 + 60 + 1 = 961. Since 934 lies between 900 and 961, its square root...

Answer to Around 30 percent of all decimal numbers start with a 1. Do you agree?

Mon, 27 Dec 2010 18:30:32 -0800

Around 30 percent of all decimal numbers start with a 1. Do you agree?

It sounds like you're mis-stating Benford's Law http://en.wikipedia.org/wiki/Benford%27s_law

Answer to Why spherical aberration is not happen in the case of a concave mirror of small aperture?

Sat, 25 Dec 2010 17:52:18 -0800

Why spherical aberration is not happen in the case of a concave mirror of small aperture?

I think it's because when you work out how much spherical aberration deviates from perfectly parabolic optics, it turns out that the normally first-order errors approach second-order near the axis. A spherical mirror is closer to parabolic at small apertures than large.

Answer to Why spherical aberration is not happen in the case of a concave mirror of small aperture?

Sat, 25 Dec 2010 17:48:32 -0800

Why spherical aberration is not happen in the case of a concave mirror of small aperture?

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Answer to Why is it an evolutionary advantage for Staphylococci to be salt tolerant? Where do most Staphylococci live as far as an environmental niche

Fri, 17 Dec 2010 09:17:27 -0800

Why is it an evolutionary advantage for Staphylococci to be salt tolerant? Where do most Staphylococci live as far as an environmental niche

Staph lives on skin. Mammals sweat salt.