Science & Mathematics - 29 July 2007

Do all spacecraft need a propellant to change their speed or direction? (Please do not take into account the spacecraft using the gravity of other planets to do this). If not, what is used and how does it work?

2007-07-29 09:45:42 · 8 answers · asked by vEngful.Gibb0n 3 in Astronomy & Space

2007-07-29 09:39:51 · 2 answers · asked by Anonymous in Physics

How many digits will there be after the . and is it repetitive?

thanks!

2007-07-29 09:36:20 · 10 answers · asked by 5674646 2 in Mathematics

How come the moon doesent have a "blue sky" like earth has; and does mars have this so called "blue sky" too?

2007-07-29 09:36:01 · 7 answers · asked by Anonymous in Astronomy & Space

Were there any unusual circumstances that cause this to happen? Is there a certain state of mind that you have to be in for this to happen?

2007-07-29 09:31:56 · 7 answers · asked by timespiral 4 in Astronomy & Space

as we can see ships and boats on sea and also objects floats on water

2007-07-29 09:18:39 · 21 answers · asked by ZAM 1 in Physics

the spider now will not eat and she is holding the leg up straight all the time she is lossing weight and my friend is worried she will die what can we do as the vet cannot help

2007-07-29 09:14:56 · 4 answers · asked by Emma M 1 in Zoology

2007-07-29 09:12:06 · 7 answers · asked by arslan s 1 in Mathematics

looking to buy a peice of land and would like to know how big it is

2007-07-29 09:11:52 · 3 answers · asked by ernesto r 1 in Mathematics

2007-07-29 09:08:02 · 7 answers · asked by altpro9 2 in Other - Science

2007-07-29 09:07:01 · 9 answers · asked by Anonymous in Physics

A nuclear scientist aquaintance told me that, contrary to popular belief, 'THE ATOM' is a myth, theory, idea etc. which, though accepted by millions as the best explanation of matter so far and even accepted as a hard fact of life by equally as many, is nevertheless unproven. Could someone enlighten me and/or point to authoritative information/websites that will give me a clear and honest and up-to-date answer on this question. Many thanks

2007-07-29 09:06:46 · 10 answers · asked by Bumblebee 1 in Physics

Assume that the light rays are parallel and the plane of the shadow is perpendicular to the light rays.

2007-07-29 09:04:01 · 5 answers · asked by Scythian1950 7 in Mathematics

In the film 2001: A Space Odyssey astronaut Dave Bowman is trapped outside the ship without a helmut. He blows the electric charges on the pod door which propels him into the open air lock of the main ship. The air lock is open to the vacuum of space and has no oxygen. Bowman holds his breath until he can close the door and flood the chamber with air. Is this scientifically possible? Or would his head explode from the lack of air pressure?

2007-07-29 08:56:28 · 12 answers · asked by Anonymous in Astronomy & Space

One of the ideas of the space station is to prove that man can live in space. So, why aren't they doing this?

2007-07-29 08:55:55 · 6 answers · asked by timespiral 4 in Astronomy & Space

2007-07-29 08:54:12 · 19 answers · asked by rahul kumar 1 in Astronomy & Space

Simplify the expression. Leave the answer with positive exponents.

2007-07-29 08:53:13 · 4 answers · asked by Jocelin 3 in Mathematics

and when will it happen? will it happen? what will happen

2007-07-29 08:49:47 · 10 answers · asked by oh! 1 in Astronomy & Space

i've recently learned a lot about optics and the working of the eye in my physics class and from this course i have realised the harm in watching tv in a dark surrounding.
The focal lenght of the eye has to adjust each time a scene on tv is changed [which lasts for about 9 seconds] so this causes strain on the eye and due to this, the eye defects worsen. i tried explaining this fact to my friends but they think its not true. i care about their eyes but they don't seem to care.
am i wrong in this?? ps all this was xcplained by my phy teacher!

2007-07-29 08:45:06 · 4 answers · asked by Anonymous in Physics

Apologies if I'm being thick, but I just haven't got a clue what the difference is!

2007-07-29 08:40:00 · 14 answers · asked by Lily & Stu Too 5 in Astronomy & Space

hi i am jim 22 years old
just done my bachelors and i am wondering what must a mech enggr. know
i have my fav subject "automobile engg" but i find people say that mech enggr must have knowledge of strength of mat, theory of machines, thermo..... well i have but not in depth coz jusut out of touch now........
what you think that i should know as mech enggr

2007-07-29 08:35:16 · 5 answers · asked by Anonymous in Engineering

What is the Y intercept of this line?

2007-07-29 08:32:09 · 9 answers · asked by bridetobebrandie 4 in Mathematics

and 4sqrt2 ?

2007-07-29 08:27:11 · 8 answers · asked by Anonymous in Mathematics

I really want to know.

2007-07-29 08:22:40 · 6 answers · asked by Anna 3 in Physics

2007-07-29 08:16:22 · 4 answers · asked by kelly g 1 in Medicine

2007-07-29 08:13:45 · 12 answers · asked by atsp 3 in Mathematics

I need to know what the difference is between them to answer these questions:

Which of the following is NOT a vector quantity?
a.) 2 miles per hour
b.) 2 pounds
c.) 2 newtons
d.) 2 kilometers per hour east
e.) 2 dynes

Which of the following is NOT a scalar quantity?
a.) 2 miles per hour
b.) 2 kilograms
c.) 2 apples
d.) 2 ounces
e.) 2 liters

I'm not looking for you to answer the questions as I already know the answers[ a.) and d.) - from the book] but I need to know the difference between a scalar and vector quantity so I can answer them myself. The book is simply a workbook and has no explanations.

2007-07-29 08:11:00 · 4 answers · asked by Anonymous in Physics

What is the answer to this equation?

2007-07-29 08:08:21 · 10 answers · asked by bridetobebrandie 4 in Mathematics

2007-07-29 08:02:14 · 3 answers · asked by Anonymous in Engineering

2007-07-29 07:58:45 · 7 answers · asked by Anonymous in Mathematics