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Science & Mathematics - 7 November 2007

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Agriculture · Alternative · Astronomy & Space · Biology · Botany · Chemistry · Earth Sciences & Geology · Engineering · Geography · Mathematics · Medicine · Other - Science · Physics · Weather · Zoology

How much electric power could be obtained from a small hydroelectric station if the elevation change was 150 meters and if 10, 000 kg of water passed through the turbines every second, with the overall efficiency being 85 %?

support your answer with equation.

2007-11-07 03:47:35 · 2 answers · asked by Anonymous in Physics

An airplane flies on a level path. There is a pressure difference of 525 Pa between the lower and upper surfaces of the wings. The area of each wing surface is about 112 m^2. The air moves below the wings at a speed of 80 m/s. Find the air speed above the wings if the weight of the plane is 117600 N.

2007-11-07 03:45:27 · 3 answers · asked by Jerry M 1 in Physics

I have a water tank made of SS(1000ltrs) and a heavy duty compressor. I just want to spray this water with a good velocity over an object that too only 10 to 15 time a minute how to make it?...

2007-11-07 03:44:37 · 3 answers · asked by Ravindran 1 in Engineering

a 5.00 kg block is pulled along a horizontal frictionless floor by a cord that exerts a force of magnitude F=12.0 N at an anglr of 25 degrees above the horizontal. What is the magnitude of the block's acceleration? the force magnitude F slowly increased. What is its value just before the block is lifted (completely) off the floor?
what is the magnitude of the block's acceleration just before is lifted off the floor (completely.

2007-11-07 03:38:26 · 4 answers · asked by magna1211@sbcglobal.net 1 in Physics

2007-11-07 03:38:00 · 14 answers · asked by elohel 2 in Weather

The recent hurricanes and gasoline issues are proof of the existence of a new chemical element. A major research institution has recently announced the discovery of the heaviest element yet known to science.

The new element has been named Governmentium. Governmentium (Gv) has one neutron, 25 assistant neutrons, 88 deputy neutrons, and 198 assistant deputy neutrons, giving it an atomic mass of 312. These 312 particles are held together by forces called morons, which are surrounded by vast quantities of lepton-like particles called
peons.

Since Governmentium has no electrons, it is inert; however, it can be detected, because it impedes every action with which it comes into contact. A minute amount of Governmentium can cause an action that would normally take less than a second to take over four days to complete.


Governmentium has a normal half-life of 4 years. It does not decay, but instead undergoes a reorganization in which a portion of the neutrons exchange places.

2007-11-07 03:37:56 · 4 answers · asked by Anonymous in Chemistry

I have never had a doctor ask me my preference before. I said to him I thought there was no difference an he assured me I was wrong
I went to my regular doctor for 3 perscriptions and he refilled them all generic w/o asking my preference

1. does it make a differenece generic vs namebrand ?
2. should my physician ask me my preference ?
3. are generics perscribed for some particular reason

2007-11-07 03:32:57 · 4 answers · asked by spider809again 1 in Medicine

This is a scientific question. Meaning that this is for a Science Fair Project. Answer as adequately as you can

2007-11-07 03:32:12 · 12 answers · asked by Anonymous in Physics

A lever is used to lift a heavy load. When a 50-N force pushes one end of the lever down 1.2 m, the load rises 0.2 m. Calculate the weight of the load

2007-11-07 03:31:03 · 1 answers · asked by Anonymous in Physics

As you drive down the road at 20 m/s you press on the gas pedal and speed up with a uniform acceleration of 1.16 m/s2 for 0.70 s. If the tires on your car have a radius of 33 cm, what is their angular displacement during this period of acceleration?

2007-11-07 03:27:02 · 6 answers · asked by Amber G 2 in Physics

What is the mean for the following questions?

1.whats the mean for: 43 41 39
2.whats the mean for: 56 57 52
3.whats the mean for: 41 46 45



Many thanks!!!

x-x-x

2007-11-07 03:24:14 · 15 answers · asked by Shake&Bake Baby 2 in Mathematics

The second floor of a house is 6 m above street level. How much work is required to lift a 300-kg refrigerator to the second floor level?

2007-11-07 03:18:51 · 1 answers · asked by Anonymous in Physics

prove that Lt x->0+ [sinx /x] is 0
and Lt x->0+ [tanx /x] is 1 where [.] represents Greatest integer function.

2007-11-07 03:17:19 · 3 answers · asked by Anonymous in Mathematics

Consider all five-digit numbers formed by using the digits 1, 2, 3, 4, and 5 once and only once in each number formed. What is the sum of all of these five-digit numbers?

2007-11-07 03:17:09 · 11 answers · asked by Anonymous in Mathematics

x squared - 14x +49

2007-11-07 03:12:37 · 7 answers · asked by Mark B 1 in Mathematics

prove Lt x->inf. cuberoot{(a+x)(b+x)(c+x)} -x is (a+b+c)/3

2007-11-07 03:09:15 · 2 answers · asked by Anonymous in Mathematics

1. a sum of £10,000 is invested at 6% for one year. Determine the value at the end of year if interest is compouned.
2.1 quarterly (every 3 months)
2.2 monthly
2.3 Weekly




2. a sum of £150 is placed at the beginning of each month in an account with an annual interest rate of 6%, compounded monthly. How much money is there in the account at the end of the first year?(clarification: at the end of the first year’ means that 12 payments have been made. The 13th payment has not been made yet)

3. you have just won £ 4000,000 in the lottery, in order to collect the money. You must choose one of the following two options: a) the whole amount right now, or b) 500,000 a year for ten years. The first payment starting exactly one year from now, assuming that annual interest rates r 5% and compounded annually, which option is best? Use the concept of present value to estimate how much option b) is worth to you right now.

4. a monopolist faces a demand function D(p) = √1-P², where p is price,
5.1 calculate the marginal revenue as a function of price. Then find the price that maximises revenue.


5.2 suppose that price is increased from p=0.1 to p=0.2, by how much does revenue change? Compare your answer with an estimate based on a linear approximation of the revenue function at p=0.1


5, for each of the following functions, find and classify the critical points. And the global maxima and minima if they exist, then sketch the function.
6.1 f(x)= x³ -18x² +33x +150. with X>=0;
6.2 g(x) = x³-18x²+33x + 150 0<=x<=12;
6.3 h(x) =(a²-x²)3/2. with –a<=x<=a and a a given real number

2007-11-07 03:07:53 · 1 answers · asked by naughty d 1 in Mathematics

RECAP: If you stand where the Earth's surface is travelling at 400mph because of the planet's spin, the air will be moving at that speed. If 'your' air is dragged northward to where the surface is moving at 390mph a westerly wind of 10mph will blow: Repeat this until you arrive at the column of rising gasifide water and air. This explains why the hurricane spins anticlockwise and how it gets its speed (but think also of the slingshot effect on the air atoms being forced to change direction). More points please, lots more are needed for the next thrilling episode, watch this space!

2007-11-07 03:05:24 · 1 answers · asked by chalky 3 in Weather

go onto this site and do problem number 8
http://www.hamilton.ie/mathschallenge/Wk3.htm

2007-11-07 03:04:25 · 3 answers · asked by irish dubliner 2 in Mathematics

how do i find the angle of intersection between the two planes given by:

3x + 4y + 5z = 8
2x - 6y - 3z = 0

all i know how to do is find the dot product of vectors, how to find their modulus and how to find the angle between them from that but i dont see how it applies here. can anybody help out?
cheers.

2007-11-07 02:53:44 · 2 answers · asked by fpa06mr 5 in Mathematics

in a 5x5 table ,how many rectangles would be there ?

How to find ?

2007-11-07 02:41:33 · 4 answers · asked by calculus 1 in Mathematics

2007-11-07 02:21:14 · 8 answers · asked by raigurusaurav 1 in Weather

2007-11-07 02:17:20 · 9 answers · asked by Anonymous in Chemistry

just joined a reputable local group.
They were even on the Maury show [was supposed to be a part of it,but couldn't make it]
Fortunately they contacted me again :o)
So am getting prepared for an upcoming investigation, my 1st one ever!!
Always have been drawn to this type of stuff waaaaaaaay b4 it "was in", whatever
Anyway, of course I do realize it is work and having patience,ect
IF YOU ARE a researcher/have exp. w/this ...
what types of uncanny unexplainable things happened??
ty

2007-11-07 02:16:58 · 5 answers · asked by deirdrefaith 4 in Paranormal Phenomena

Thank you for the last answer. I finally understood it. Now I need help with this one

2007-11-07 02:12:22 · 6 answers · asked by danielle 1 in Mathematics

Do they die outside in the winter? Do they all die if they receive sun?

2007-11-07 02:10:41 · 7 answers · asked by Jorge H 2 in Biology

2007-11-07 02:09:19 · 18 answers · asked by Anonymous in Earth Sciences & Geology

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