Science & Mathematics - 27 September 2007

what word do we use to describe caring for our natural resources such as air, water, soil, minerals, fuels, plants, and animals by using them carefully so that we will have them now and in the future must start with C

2007-09-27 04:41:11 · 4 answers · asked by Anonymous in Geography

ln (1+x) = 1+ lnx

Thanks

2007-09-27 04:36:50 · 5 answers · asked by Mystic healer 4 in Mathematics

2007-09-27 04:35:30 · 2 answers · asked by airplanesluvbluesky 1 in Earth Sciences & Geology

HY I'm from Romainia and i want to ask 1 question : HOW CAN I SOLVE THIS??????????? : "" 2mx+3=3m+x ""where m is part of R
PLS help i realy don't have any ideas!! could you help????

2007-09-27 04:34:30 · 2 answers · asked by THE BMW DUDE 1 in Mathematics

dy/dx= 1 / [x^2 - 1]

y=?

2007-09-27 04:31:39 · 5 answers · asked by Chocolate Strawberries. 4 in Mathematics

when we roll a piece of material,for instance, paper or plastic, it rolls back. What is the force or energy involved? Is there any scientific theory behind such phenomenon?

2007-09-27 04:30:31 · 2 answers · asked by howard c 1 in Physics

a 72 degree room, which one will reach room temperature first? Why? This debate has occupied 20 minutes of mine and my co-workers time... please help us answer this so we can get back to work!

2007-09-27 04:22:11 · 9 answers · asked by Anonymous in Physics

2007-09-27 04:19:02 · 3 answers · asked by lacrosse13bb 3 in Engineering

Hollow iron sphere full of 1,000 liters of liquid sodium @400C. The iron sphere has an initial average temperature of 50C, and a total heat capacity of 10,000kJ/C. The sphere is submerged in 10,000 liters of water @25C. How much water will flash to steam in a room at a vacuum of 25" Hg?

http://s223.photobucket.com/albums/dd78/floodtl/?action=view¤t=LatentHeat.jpg

2007-09-27 04:18:04 · 3 answers · asked by Anonymous in Physics

A crystal growth furnace is used in research to determine how best to manufacture crystals used in electric components for the space shuttle. For proper growth of the crystal, the temperature must be controlled accurately by adjusting the input power. Suppose the relationship is given by the following equation, where T is the temperature in degrees Celsius and w is the power input in watts.
T(w) = 0.1w^2 + 2.156w + 20

(a) How much power is needed to maintain the temperature at 204°C? (Give your answer correct to 2 decimal places.)

(b) If the temperature is allowed to vary from 204°C by up to ±1°C, what range of wattage is allowed for the input power? (Give your answer correct to 2 decimal places.)
smaller value=?
larger value=?

2007-09-27 04:15:53 · 2 answers · asked by lady_divine@sbcglobal.net 1 in Mathematics

3NO2 + H2O -> 2HNO3 + NO

If 74g of NO2 reacts with 100 g H20, 23 g gaseous NO are made. Calculate % yield.

Find Limiting Reagent
74 g NO2 (1 mole NO2 / 46 g NO2) = 1.61 mole NO2
100 g H2O (1 mole H2O / 18.02 g H2O) = 5.55 mole H2O
NO2 is the LR

Convert mole NO2 to g NO
1.61 mole NO2 (1 mole NO / 3 mole NO2) = 0.54 mole NO
0.54 mole NO (30 g NO / 1 mole NO) = 16.1 g NO

Percent Yield
23 g NO / 16.1 g NO * 100% = 142.9%

THE SECOND ONE IS
3NO2 + H2O -> 2HNO3 + NO

If 2.2 kg of NO2 reacts with 1.2 kg H2O, 0.23 kg gaseous NO are made. Calculate % yield.

Find LR
2200 g NO2 (1 mole NO2 / 46 g NO2) = 47.8 mole NO2
1200 g H2O (1 mole H2O / 18.02 g H2O) = 66.6 mole H2O
NO2 is the LR

Convert mole NO2 to g NO
47.8 mole NO2 (1 mole NO / 3 mole NO2) = 15.9 mole NO
15.9 mole NO (30 g NO / 1 mole NO) = 477 g NO

Percent Yield
230 g NO / 477 g NO * 100% = 48.2%

ty for your help!

2007-09-27 04:13:33 · 2 answers · asked by Saegis 2 in Chemistry

2007-09-27 04:13:12 · 2 answers · asked by Mr C 1 in Astronomy & Space

How do you integrate:

dy/dx= 1 / [x^2 - 1]

2007-09-27 04:12:03 · 4 answers · asked by Chocolate Strawberries. 4 in Mathematics

You are confronted with the following question: One mole of an ideal gas is sealed in a 22.4- L container at a pressure of 1 atm and a temperature of 273 K . The temperature is then increased to 305 , but the container does not expand.

also what is the appropriate formula to solve this problem

2007-09-27 04:11:06 · 3 answers · asked by Anonymous in Chemistry

2007-09-27 04:09:57 · 12 answers · asked by kchotty 2 in Mathematics

(7x+3)/3 < 43 I just need help on how to simplify the left side. I tried multiplying it by 3/1 but that doesn't give me the right answer. Please help! Thanks!

2007-09-27 04:09:45 · 5 answers · asked by ♫ ∫aoli 4 in Mathematics

Hey everyone someone please help. I asked my professor about this in class and he didnt listen to me just interupted so i still dont know. here it is
2 transparent materials having indexes of refraction 1.27 and 1.31 are placed in to contact. Is it possible for total internal reflection to occur at the boundry between the two materials? In either case, be specific about details or constrants.

Some one help all i know is it has something to do with n1 (v1)=n2(v2) or something like that.

2007-09-27 04:08:27 · 2 answers · asked by DP 3 in Physics

i suckk

2007-09-27 04:07:02 · 21 answers · asked by K_Dizzle35** Y!A_MoSt HaTed!* 5 in Mathematics

can u plz tell how many inches equal one kilometre???

2007-09-27 04:00:30 · 12 answers · asked by shubhangi 1 in Mathematics

I am looking for a kind material that has the following properties:
- isn't gas or fluid
- doesn't react with water
- doesn't have negative effects on humans
- has low weight and doesn't sink in water
- Has a similar or smaller density than water.
- Is solid, it isn't powder or something you can crush when you touch it


If your answers won't fit i'll add more details. Thanks in advance.

2007-09-27 03:59:58 · 7 answers · asked by Anonymous in Other - Science

2007-09-27 03:55:44 · 4 answers · asked by Grace 2 in Mathematics

I've be recently told that Cancerians are strongly effected by the Moon. Over the last week and the beginning of this week my moods have been all over the place. Last night there was a full moon and today I'm back to normal.

2007-09-27 03:54:52 · 20 answers · asked by Anonymous in Astronomy & Space

Hi, need some help with finding asymptotes. Thanks.

f(x)= -4x / x^2 + x - 6

Need horizontal and verticle. thanks for your help. im stuck

2007-09-27 03:52:23 · 4 answers · asked by MysteryMan 1 in Mathematics

I do not care about one particular species of the bear or shark - every species combined would be best.

Thanks

2007-09-27 03:52:06 · 4 answers · asked by debracramer 1 in Zoology

We all know hubbles constant, and hubbles law, right? But what is the purpose of it, besides the relationship between distance, velocity and his constant. Why did Edwin invent hubble's constant?

What's a red shift/Blue shift? I'm having problems understanding that aswell. So as the galaxy moves away, the light it emmits shifts towards the red spectrum, but why does the spectrum shift?

The probable origins of the universe are most likely from the Big Band, and I see how Hubble said that with these red shifts, the distance is getting greater between us, which suggests that the universe is expanding.

Also, outta curiousity, if the universe was expanding, including us, wouldn't the density change = 0, relative to all matter?

And if black holes squash matter to the size of a hydrogen atom, wouldn't that mean that the amount of matter is gonna be reduced to nothing, and energy is destroyed in the process, which cancells the law of conservation of energy?

2007-09-27 03:51:27 · 4 answers · asked by Suki 4 in Astronomy & Space

....one with a life?

2007-09-27 03:49:34 · 14 answers · asked by Anonymous in Astronomy & Space

how do i integrate:

( sin (1/x) ) / x^2 dx

i know i take the substitution of u=1/x becos it says in the question.

:-)

2007-09-27 03:49:20 · 3 answers · asked by hyperpringle 1 in Mathematics

The generator has to run at constant speed. How this is achieved when the wind speed is either toolow or too high?

2007-09-27 03:47:31 · 6 answers · asked by sitaradha v 1 in Engineering

Think The Recent Meteorite Crash really is a "Mass Hysteria"?
Mass Hysteria? Alien Related? Andromeda Strain? New Discovery Government Cover-up? Making People Sick true or false?
[Scientists say the "sickness" that struck locals after a meteorite crash is mass hysteria.??]
http://news.yahoo.com/s/space/20070927/sc_space/meteoritecrashbreedsmasshysteria

2007-09-27 03:47:00 · 9 answers · asked by Solo Preguntar 3 in Astronomy & Space

I am at my school right now,and I have a test next period,and I need to know this question. Please help.

2007-09-27 03:46:35 · 5 answers · asked by Anonymous in Geography