Science & Mathematics - 5 September 2007

Is it possible when staying near a spring and meditating or just admiring the flow and the noise of the water to hear things as said by human voice/possible as so called electronic voices by the phone/ , but indeed there is noone around.The same pfenomena as when listening the noise from the rain.
May be someone knows about ancient pracices for clairvoyance or smth similar or a mediumship?

2007-09-05 07:02:59 · 3 answers · asked by ThanksBelit 2 in Parapsychology

2007-09-05 06:57:51 · 8 answers · asked by Alexander 6 in Physics

I used the formula costheta=u*v/IIuII*IIvII, and came up with the answer of 35.86 degrees, but the book is saying this answer is incorrect. Does anyone know what I'm doing wrong?

2007-09-05 06:53:59 · 4 answers · asked by Awesometown13 1 in Mathematics

Why are rainbows diffent colours?

2007-09-05 06:51:30 · 11 answers · asked by Lapperz 1 in Weather

HI! I'm pissed, as usual, about trigonometry. This time, it's about the reduction formula, a.k.a. the most idiotic thing I've ever seen in my life. I thought that all was fine, but now I've come across some real problems. First of all, my book does not explain how to use the reduction formula. All it does is give the formula and then show 1 problem worked out.

What I've surmised from that (and it has served me well thus far) is:

√(a² + b²)sin( x + α)

Great. I get the whole "√(a² + b²)sin( x" part, but I seem to be having trouble with the "+ α" aspect of it.

What I would guess, solely from my stupid book, is that to get α, you find cos α by doing a/[√(a² + b²)]. I need to know:

1) How do you know which value of α to use? Often times there is more than one angle for which cos = a/[√(a² + b²)].

2) What do you do when the problem is NOT in the form of a sin x + b cos x, but rather a sin x - b cos x? What about if a is negative?

Thank you so much! I'll pick a best answr!

2007-09-05 06:51:18 · 2 answers · asked by Anonymous in Mathematics

were constantly drilling for oil taking and taking it from the earth to burn it away into the atmosphere so it is no longer on or in the earth,
plus we take big rockets and satellites off the earth again taking away from the earth.

Are we not making the earth lighter...whill this cause any effects?

2007-09-05 06:48:05 · 17 answers · asked by Anonymous in Earth Sciences & Geology

I need to obtain a graphing calculator for Calculus. What is the best one to get? Theres so many I don't know where to begin.

2007-09-05 06:46:34 · 10 answers · asked by Fashionisto Billy 4 in Mathematics

2007-09-05 06:43:41 · 8 answers · asked by JacQuan E 1 in Mathematics

My physics teacher told me that 1 = 2 because:
0 = 0
a^2 - a^2 = a^2 - a^2
a(a-a) = (a+a)(a-a)
cancel out (a-a)
a = a+a
divide by a
1=2????
how is this possible and how can I disprove it??

2007-09-05 06:42:05 · 14 answers · asked by Hehe 2 in Mathematics

Simplify:

cos(A+pi/2)+sin(A+pi/2)

2007-09-05 06:41:26 · 5 answers · asked by Anonymous in Mathematics

2007-09-05 06:40:19 · 8 answers · asked by bratt200507 1 in Mathematics

2007-09-05 06:39:13 · 5 answers · asked by Cortez M 2 in Mathematics

An insulated tank is filled with a solution containing radioactive cobalt. Due to the radioactivity, energy is released and the temperature T (in deg C) of the solution rises with time t (in h). The following equation expresses the relation between temperature and time for a specific case: dT=(20.0-2.50t)dt. If the initial temperature is 65 degrees C, what is the temperature 12 hours later?

2007-09-05 06:37:19 · 3 answers · asked by Anonymous in Mathematics

/ means fraction
Can not find LCD

2007-09-05 06:36:28 · 9 answers · asked by Gucci 2 in Mathematics

it only displays my answers in fraction format and not in decimal format, how do i fix this?

2007-09-05 06:34:21 · 13 answers · asked by Anonymous in Mathematics

1. If arizona is 114,000 square miles, which accounts for 3.07% of the United States. How big is the united states? How did you do this?

2. If a computer cost $1750.00 and the tax was 8.05% how much is the tax?

2007-09-05 06:32:12 · 8 answers · asked by Anonymous in Mathematics

Only one isotope of this element occurs in nature. One atom of this isotope has a mass of 9.123x10^-23g. Identify the element and give its atomic mass.

2007-09-05 06:30:52 · 3 answers · asked by live in the moment 2 in Chemistry

2007-09-05 06:29:49 · 4 answers · asked by Arkesha S 1 in Mathematics

Flying with the wind, a plane takes 1hr to go from city A to city B. Flying against the wind, the plane takes 2hrs to go from city B to city A. The trip from A to B is 200 miles. What is the speed of the plane and the wind?
a = speed of plane, w = speed of plane

I've only been able to get this far..
(a+w)*1=200
(a-w)*2=200

a+w=200
2a-2w=200
I know I need to substitute the problems then plug that number back in to get the second answer, but how do I do it?

2007-09-05 06:28:41 · 8 answers · asked by tina 3 in Mathematics

What is the chance of having no pair of cards of the same rank next to each other in a hand of five cards (from a deck of 52 cards) ? According to me it's impossible to calculate unless you check all the possibilities.

2007-09-05 06:27:58 · 5 answers · asked by ?????? 7 in Mathematics

The sales (S) of a product as a function of the time (t) (in weeks) is given by S=[2300(5t+1)] / (2t+5). Find the instantaneous rate of change of (S) with respect to (t) for t= 9 weeks.

2007-09-05 06:27:55 · 2 answers · asked by Anonymous in Mathematics

Two roads intersect at right angle.
First car is at intersection, driving North at speed 30mph
At this same moment the second car is 1000 feet away from the intersection, approaching from West at speed 40mph.

2007-09-05 06:25:35 · 7 answers · asked by Alexander 6 in Physics

ok, once again, i don't understand what my teacher has done here.

6x^3y-24x^2y
-------------------
9x^2y^2+27xy^2


he simplified, so that we'd have:

2x-24x^2y
--------------
3y+27xy^2


but then he wrote
=2x(x-4)
-------------
3y(x+3)


i understand that he just factored, but why is it just (x-4) and (x+3). i missed the explanation.

2007-09-05 06:25:00 · 4 answers · asked by alexie. 4 in Mathematics

Twice the sum of a number and 3 is the same as 1 subtracted from the number. find the number??

2007-09-05 06:19:46 · 12 answers · asked by Desiree S 1 in Mathematics

how many litres makes a glass of water?

2007-09-05 06:19:38 · 7 answers · asked by sendfrancis 1 in Mathematics

according to some certain rule, which number should be put in it, why?
12（56）16
17（ ）21

2007-09-05 06:16:41 · 6 answers · asked by Gabriel 1 in Mathematics

I would slso like to know where this dense mass of energy cam from and what surrounded the mass. Was it sitting in empty space?

I think that even if you got beyonfd the universe that you would still go on infinitely in to empty space. There may be no energy or mass, but you are not going to run in to a brick wall/

2007-09-05 06:10:13 · 9 answers · asked by Anonymous in Physics

At what strength does hydrochloric acid fume. When I did some research, I noticed that the literature refered to 36% HCl and stronger as "fuming". What determines if the HCl will fume? Does it have to do with vapor pressure of the water and the HCl?

2007-09-05 06:08:36 · 4 answers · asked by Skrap 3 in Chemistry

I've got this quadratic to solve as part of a problem but can't do it- any help please?!
3s^2 - 925s + 7500 = 0
Obviously you need to use the general solution but I can't do this with b being negative. Please help.

2007-09-05 06:07:16 · 7 answers · asked by Ash 2 in Mathematics

2007-09-05 06:05:10 · 4 answers · asked by tpooram 3 in Other - Science