Science & Mathematics - 29 July 2007

Can someone explain me the Birthday paradox?
I used a formula with:
n=23
k=0
p=1/365
than i calculated 1-p and got about 6%

2007-07-29 19:30:17 · 3 answers · asked by Anonymous in Mathematics

pinhole camera..................move a pinhole camera closer to or farther from a lamp...waht do you observe on the screen?how would you explain it?
do you think you can make the image on the screen in other positions?HOW?

2007-07-29 19:26:29 · 1 answers · asked by Kauori 1 in Physics

If something was to appear out of the clear blue, like "poof", and its not called magic, then what is it called. Its not an optical illusion, because its actually there, but not just a trick to the eye. I called it magic, but people say that magic is an illusion

2007-07-29 19:20:10 · 14 answers · asked by Anonymous in Astronomy & Space

"A thin disk, mounted on a frictionless vertical shaft of negligible rotational inertia, is rotating at 636 revolutions per minute. An identical disk (that is not initially rotating) is dropped onto the first disk. The frictional force between the disks causes them to rotate at a common angular velocity. Find this common angular velocity. NOTE: Be careful with your units!"
Since it is stated that there is no moment of inertia, the common angular velocity is the same as the first velocity which is 66.6 rad/s (converted it into radian/s). If this is not correct, please explain to me. Thank you.

2007-07-29 19:17:13 · 2 answers · asked by Anonymous in Physics

help me evaluate this. this is the only one I haven't answered

4) lim (sqrt1+sqrtx)/(sqrt1+x)
x-->+infinity
Note:
the numerator is a single term also the denominator

2007-07-29 19:15:14 · 4 answers · asked by Patricia 2 in Mathematics

Keep in mind that I never knew that citronella was a plant, I only thought it was a bug-repelling candle.

2007-07-29 19:14:46 · 3 answers · asked by CEKNB 3 in Botany

I'm pretty sure that I understand the concept, but I'd like to be sure about this. My question pertains to how gravity increases as the mass of an object is compacted into a smaller and smaller space (i.e. a black hole). Does the gravity increase because the space-time distortion becomes steeper and steeper as the object becomes smaller?

This is how I'm picturing it (though its probably way out of scale!). Say there is an object that is as large as the center of a plate that has a mass of x which distorts space-time to a curvature equal to the curved edges of a plate. As one may clearly see this is not too steep of a curvature. On the other hand, if an object such as a shot glass has the same mass of x and is the size of the bottom of the shotglass then the space-time distortion of the object is equal to the sides of the glass. Thus, the shotglass object requires more energy to escape from inside of the glass than the energy required for an object to escape the plate. Am I correct?

2007-07-29 19:14:38 · 3 answers · asked by bobo! 1 in Physics

Ive heared that reef/coral life is becoming virtually extinct. Is that true? And does owning a salt water tank contribute to the problem?

2007-07-29 19:13:08 · 2 answers · asked by Anonymous in Zoology

2007-07-29 19:05:28 · 8 answers · asked by Anonymous in Other - Science

2007-07-29 19:01:21 · 6 answers · asked by Anonymous in Earth Sciences & Geology

how many diagonals are there in
a) a quadrilateral?
b) a pentagon?
c) a hexagon

2007-07-29 18:47:53 · 3 answers · asked by Anonymous in Mathematics

In a nozzle the velocity is incresed with the expense of pressure.

2007-07-29 18:41:52 · 3 answers · asked by nish 1 in Physics

and what is the average rainfall each year

2007-07-29 18:41:50 · 1 answers · asked by Claudio Mota III 5 in Weather

Why do we see an arc (shape)?

Why do we sometimes see two arcs?

And where exactly do the orginate from? start from? a cloud?

Why exactly always the same bands of colour?

2007-07-29 18:39:37 · 6 answers · asked by Anonymous in Weather

You buy 1 ticket for $1 out of a lottery of 1000 tickets where the prize for the one winning ticket is to be $500. What are your expected winnings?

a. -$.40
b. $0
c. -$1.00
d. -$.50

2007-07-29 18:38:00 · 6 answers · asked by mia 1 in Mathematics

n=0 Σ ∞ -1^(n+1)*e^n / 3^(n+1)


Determine whether series is convergent or divergent, and if convergent find its sum.

I think it's convergent due to alternating series test, but I can't figure out its sum...

2007-07-29 18:21:33 · 2 answers · asked by Anonymous in Mathematics

Scientists and scholars, especially those who are religious, what do you think should be done to address the crisis of the attack on the theory of evolution by religious fundamentalists and creationsist pseudoscientists?

I understand those who would answer "education", but I have tried that and have noticed that most creationists lack precursury education inorder be properly argued against regarding evolution. Most people lack the knowledge to understand even just basic genetics and biogeography, and so creationist find it easy to pursue popaganda since they have with them "common sense".

2007-07-29 18:19:20 · 12 answers · asked by pecier 3 in Biology

2007-07-29 18:18:49 · 3 answers · asked by Anonymous in Botany

example: ph=3.77, pka= 3.85, acid [.10]. what will the concentration be for the base?

P.S. I can solve it without this henderson equation but I want to know how to manipulate this equation.

2007-07-29 18:18:48 · 2 answers · asked by Anonymous in Chemistry

How many 6 digit numbers are possible using the following numbers

a)111234
b)133445
c)666678

2007-07-29 18:18:30 · 2 answers · asked by Anonymous in Mathematics

Determine whether the series is absolutely convergent, conditionally convergent or divergent.

a) n=1 Σ ∞ (-1)^n * 2n/(4n^4 +3)^.5

b) n=1 Σ ∞ (-1)^n * (2^n)/(n!)

any help would be appreciated!

2007-07-29 18:16:13 · 2 answers · asked by Anonymous in Mathematics

Are they also known as Indus Valley Civilisations; are they the same thing?

2007-07-29 18:14:37 · 3 answers · asked by Clarity. 3 in Geography

If I take a small piece of dry ice, and put it in 5 table spoons of water in a glass what would happen?

2007-07-29 18:13:15 · 9 answers · asked by Anonymous in Chemistry

I think its used for lawns and on instant cold packs. What else can you use it for?

2007-07-29 18:11:43 · 4 answers · asked by Anonymous in Chemistry

and then factor:

x^2 - 7xy

2007-07-29 18:10:52 · 5 answers · asked by Pimpmeister 1 in Mathematics

meaning that the coint will be heads at least 4 of the 6 times?

2007-07-29 18:10:37 · 3 answers · asked by daniel k 2 in Mathematics

A manufacturer needs to make corrugated metal sheets 36inches wide with cross sections in the shape of the curve

y = .5sinπx, 0≤x≤36

How wide must the original flat sheet be for the manufacturer to produce these corrugated sheets? Set up but do not evaluate the integral.

2007-07-29 18:08:36 · 2 answers · asked by Anonymous in Mathematics

Preferably for the undergrad level and oriented to mathematicians. I already know the Spivak, Courant, Banach, Kuratowsky, Apostol, Lang, Strang, Letihold Swokowski, Zill. If you know of another one it would be greatly appreciated.

2007-07-29 18:05:51 · 5 answers · asked by Anonymous in Mathematics

2007-07-29 18:03:14 · 3 answers · asked by Anonymous in Mathematics

Between what lines of latitude and longitude lay the 48 contiguous states of the United States?

2007-07-29 18:03:01 · 5 answers · asked by Gloz 1 in Geography