Science & Mathematics - 15 January 2007

Some natural numbers can be expressed as a difference of two squares, but others cannot. For example 12=4^2 - 2^2, but 10 cannot be written as a difference of two squares. I need a way to determine if a number can be determined by a difference of squares.

2007-01-15 10:31:59 · 5 answers · asked by brennen 1 in Mathematics

im making a prototype of an invention and i will be machining the parts with a lathe. the plastic should be soft and not brittle. Delrin, acrylic, and teflon ptfe rods are NOT an option. Unless otherwise convinced. dimensions for the parts are 21mm in Diameter so a 1" Diameter Rod will be acceptible.

2007-01-15 10:28:29 · 4 answers · asked by jlp.media 3 in Engineering

Mars, Venus, Saturn, Jupiter, Mercury, Uranus, Pluto... ??

Mine's *Venus* ...

What's Your Favourite Planet??

2007-01-15 10:27:02 · 18 answers · asked by *Hilary_Duff_Honey* 2 in Astronomy & Space

A SAMPLE A CYANIC ACID, HCN CONTAINS 3.33*10^23
ATOMS. HOW MANY MOLES OF CYANIC ACID ARE IN THE SAMPLE? HINT: FIND THE NUMBER OF MOLECULES FIRST

2007-01-15 10:26:21 · 2 answers · asked by Anonymous in Chemistry

2007-01-15 10:22:09 · 18 answers · asked by Anonymous in Astronomy & Space

is it possible for to organisms to have diffrent phenotypes and the same genotyps? why?

2007-01-15 10:21:59 · 3 answers · asked by mano558 5 in Biology

How are the different bones in the hand connected? Joints connect bone to bone and ligaments connect bone to muscle. But, the hand seems different, why is this?

2007-01-15 10:20:07 · 5 answers · asked by Anonymous in Biology

If so could you please explain??

2007-01-15 10:19:04 · 3 answers · asked by Tracey Lee ♥ 2 in Mathematics

so this universe started with the big bang, right? What was there before the big bang?

2007-01-15 10:16:59 · 20 answers · asked by wally 3 in Astronomy & Space

2007-01-15 10:16:50 · 15 answers · asked by Anonymous in Physics

2007-01-15 10:16:06 · 10 answers · asked by josh j 1 in Mathematics

A 2.5 g sample of He is held in a 3.000 L closed container at 20.0 degrees celcius. The temperature is increased to 60.0 degrees celcius. If the final volume is 3.000 L and the final pressure is 1.874 atm, what was the initial pressure of the gas?

2007-01-15 10:15:55 · 5 answers · asked by Anonymous in Chemistry

2007-01-15 10:13:42 · 3 answers · asked by Anonymous in Biology

2007-01-15 10:13:14 · 15 answers · asked by Anonymous in Mathematics

Will someone please explain nuclear equations to me? I don't get them. When you're bombarding something with particles to make it produce new stuff (in nuclear transformation, I think) How do you get it, the products and the reactants?

2007-01-15 10:13:11 · 3 answers · asked by Coolest person alive 1 in Chemistry

Imagine that you are given the opportunity to communicate with a world that has the tech level of, say, the middle ages. Or, say, a fantasy world such as Middle-Earth or The Legend of Zelda's Hyrule. (The latter was actually what I was originally thinking of.) You can ask questions to ascertain to exact science/tech level there. Now then: if you wanted to accelerate their technological progress, what advice would you give them? (Trying not to come off to them as a total nutcase.)

The printing press would obviously be important, if they don't have it already. Ditto for the steam engine - but what would you tell them? That steam can be used to turn wheels and paddles? To separate the condenser? How to make a governor for it? And then electromagnetism; would you tell them to study lightning carefully, observe its effects on compasses, mix metals? Probably most important would be simply the scientific method. Your thoughts?

2007-01-15 10:12:54 · 1 answers · asked by Shay Guy 2 in Other - Science

well all know that inductor transformers don't work with dc currents and the battery is a dc power source and the ignition coil is an inductor transformer (just to start the engin it has to step up the voltage) so how does it convert the current from dc to ac to be compatiable with the ignition coil

2007-01-15 10:11:10 · 11 answers · asked by macgyver 1 in Engineering

!st person gets it

2007-01-15 10:10:46 · 33 answers · asked by Anonymous in Mathematics

I've been bitten by a jelly fish already, but I recently went to the beach and in the water recieved an electrically shock
that lasted 5-10 minutes throughout my entire body..it was different then a jelly fish bite and there were no welts or scars..what could it have been??

2007-01-15 10:09:08 · 11 answers · asked by a_e_n_87 1 in Zoology

One line can divide a plane into two regions. Two lines can divide a plane into four regions. Three lines intersecting at a point can divide a plane into six regions, BUT you can get more regions than that if the lines don't intersect at a single point.

The question: If you use SIX LINES, what is the MAXIMUM number of regions into which you can divide the plane?

10 points will go to the person with the correct answer and I will not choose a best answer until next Monday at the earliest. If possible, I would really appreciate a sketch of the number of regions you came up with the answer. Thank you for any help I can get.

2007-01-15 10:09:00 · 8 answers · asked by poker5495 4 in Mathematics

AN ANT MOVES A DISTANCE OF 39.4 CM IN 7.3 S .WHAT IS ITS SPEED?

2007-01-15 10:06:52 · 19 answers · asked by amanuel m 1 in Physics

It seems to be a fact that we have to dig a certain amount to find ancient buildings, roads, tools, etc. The deeper we go the older the civilization. For example, in Barcelona there is a museum containing an ancient Roman town with houses, streets, etc. The problem is that it is now two flights down from current street level. Obviously at the time it was built it was on the surface. So what's the deal? It seems that the earth is constantly growing and covering up old stuff. Where does all this extra dirt come from? This appears to happen everywhere. Can anyone explain?

2007-01-15 10:06:05 · 7 answers · asked by fg 2 in Earth Sciences & Geology

the longest bicycle in the world was built in new zealand in1988. it is more than 20m in length. has a mass of 340 kg and can be ridden by 4 people at a time. suppose four people are riding the bike at a velocity of 12 km/h southeast when they realize that the street turns and that the bike wont make it around the corner. all four riders jump off the bike at the same time and with the same veloctiy (9.0 km/h northwest as measured relative to earth. if the combined mass ofthe riders is 260 kg, what is the ike's new velocity immediatly after the riders jump off?

2007-01-15 10:05:01 · 3 answers · asked by socom_lover 2 in Physics

Is the universe actually expanding or are we way off on that one? Just because we see red shift doen't mean that the microwave radiation is red shifted radiation from the formation of the univers. Surely it could be anything and this is all hypothetical?

2007-01-15 10:04:24 · 28 answers · asked by Moi? 3 in Astronomy & Space

I know that the gas constant used in the ideal gas law is 8.31 kPa x L/ mol x K, but does that apply to all gases? Or do some gases have different R values?

2007-01-15 10:04:02 · 4 answers · asked by Anonymous in Chemistry

2007-01-15 10:03:56 · 13 answers · asked by necro 3 in Geography

A micrometer is a unit used to measure very small lengths. On micrometer is equal to 10 (-6) THAT IS AN NEG EXPONENT SIX) The width of human hair measures about 50 micrometers. Find this measure in meters. Write your answer in scientific notation.

thanks a bunch.!:>

2007-01-15 10:02:28 · 5 answers · asked by curiousgeorge2 2 in Mathematics

2007-01-15 10:02:04 · 6 answers · asked by Anonymous in Geography

Such as Ponds, Streams, Rivers, lakes etc.

2007-01-15 10:01:45 · 2 answers · asked by Convex Converse 1 in Biology

2007-01-15 10:00:19 · 1 answers · asked by Selane ® 4 in Physics