Science & Mathematics - 26 September 2007

I did an experiment in chem class in which i found the mass of a sealed flask with air in it, then replaced the air with oxygen and found the mass of that. The mass of the flask + O2 is less than just the flask. Did i do something wrong?

2007-09-26 13:56:09 · 3 answers · asked by mango 2 in Chemistry

Describe the electron distribution in a polar-covalent bond and its effect on the partial charges of the compound.

2007-09-26 13:55:16 · 1 answers · asked by Anonymous in Chemistry

1) f(x) = 5x + 6

2) {(x,y) | 4x+ 3y = 9}

3) Show that x = y^2 is not a function. Do not give numerical ordered pairs.

Thanks.

2007-09-26 13:51:34 · 1 answers · asked by Anonymous in Mathematics

.........{ 0, 0 < t < 1
f(t) = {
.........{ 2t - 2, t > 1

Plz ignore the "......."s! Plus : the three " { "s should be just one big " { ".

Question : Find (Laplace transform of) : L{f(t)}

Please help - I have no idea even where to start here!
Thanks.

2007-09-26 13:50:58 · 3 answers · asked by Anonymous in Mathematics

2007-09-26 13:50:20 · 1 answers · asked by Yuri ^_^ 5 in Medicine

2007-09-26 13:50:12 · 3 answers · asked by DJS 1 in Zoology

I've been told by two doctors that I might have high blood pressure and to get it checked out. I constantly have readings of 135/70 areas. I was wondering if anyone knew why my diastolic pressure would be higher than normal and systolic lower than normal, or if there are any conditions this might be caused by. I am perfectly healthy and have been a gymnast for 12 years. I am in peak physical condition yet have this blood pressure. Thanks

2007-09-26 13:45:27 · 7 answers · asked by Dub 4 in Medicine

2007-09-26 13:42:06 · 4 answers · asked by marquel k 1 in Biology

4x^2-9

2007-09-26 13:41:45 · 7 answers · asked by jfourline6 1 in Mathematics

if you know this very well, pls try to give me a clear answer...in simple words. i cannot figure this out.
''you are on a boat which is crossing the Prime meridian. the altitude of polaris is 50 degrees. explain how you know the boat's location is 50 degrees north latitude and 0 longitude.''
..duh cuz they told us? lol
pls pls help. thanks.

2007-09-26 13:35:55 · 1 answers · asked by curtismayfield? 2 in Earth Sciences & Geology

i want it to work for any liquid or gas

2007-09-26 13:33:08 · 3 answers · asked by earl_you_echo 1 in Engineering

I know that when a neutron bombards a U235 nucleus, its fissions because it's unstable, but U238 doesn't. Or at least it takes more energy for it to fission. How? Shouldn't it be easier since it is bigger, and the nuclear force is weaker? Isn't it?

2007-09-26 13:31:21 · 2 answers · asked by shish2kabob 2 in Physics

In the philosophy of measurement, we use many indeffinite forms of measure such as vast, big, large, miniscule, etc. What determines these measurements?

2007-09-26 13:27:12 · 4 answers · asked by Sophist 7 in Astronomy & Space

2007-09-26 13:22:23 · 5 answers · asked by marvin b 1 in Engineering

just boss??? or zoo manager??

2007-09-26 13:21:33 · 7 answers · asked by guitar_crave 1 in Zoology

2007-09-26 13:18:00 · 5 answers · asked by Anonymous in Earth Sciences & Geology

2007-09-26 13:17:55 · 6 answers · asked by Anonymous in Chemistry

Suppose that in the Atwood setup a string is attached to the bottom of a mass (m1) while the string is looped around a pulley (considered to be friction and weightless) and a constant force f is applied, retarding the upward motion of m1. If m1 = 5.10 kg and m2 = 10.20 kg, what value of f will reduce the acceleration of the system by 50%?
f = ? N

2007-09-26 13:16:57 · 1 answers · asked by Anonymous in Physics

2007-09-26 13:16:42 · 2 answers · asked by Anonymous in Chemistry

describe the symmetry of y=sin x

2007-09-26 13:12:42 · 3 answers · asked by Anonymous in Mathematics

Imagine 2 rooms, 1 with 3 switches & the other with 3 light bulbs. Each switch controls 1 of the light bulbs. However, b/c the light bulbs are in a different room, you can't see immediatly which switch controls which light bulb.
Your task is to figure out which switch controls which light bulb. You can spend as much time as you like in the room with the light switches, but eventually you must go into the room with the light bulbs. Once you enter the room with the light bulbs, you can't return to the other room with the light switches. After entering the room with the light bulbs, you have only 30 seconds to figure out which switch controls which light bulb.
How do you do it?

2007-09-26 13:10:40 · 2 answers · asked by **Tiff_Tess** 1 in Physics

what are the relevant formulas and constants necessary to solve this problem?

2007-09-26 13:08:21 · 2 answers · asked by Gruntled Employee 6 in Chemistry

i found that it could be done with vinager and salt orbaking soda is this true?

2007-09-26 13:06:29 · 4 answers · asked by hellbrngr 1 in Chemistry

what is the permeability of the potato cytoplasm with reagrds to sucrose and water? Is it permeable to water, but not sucrose??

2007-09-26 13:05:51 · 1 answers · asked by Anonymous in Other - Science

If you have

-cos^2 + -sin^2x

does it equal a

-1 ?

2007-09-26 13:03:52 · 3 answers · asked by Anonymous in Mathematics

If a potato slice is placed in tubes with water and varying amounts of salt, will the higher concentrations of salt increase or decrease the mass of the potato slices and why?

2007-09-26 13:03:51 · 1 answers · asked by Anonymous in Other - Science

a) the force of gravity pulling down on a book?
b)The force of a helicopter blade pushing down on the air?
c) the force of a hammer on a nail?
d)the force of air resistance acting on a thrown baseball?

2007-09-26 13:00:57 · 4 answers · asked by TheLostOne 3 in Physics

This question is about alternating series. I understand that an alternating series converges if the limit tending to infinity is 0, and if the terms are decreasing throughout. If for a series, one of these tests for convergence fails and the alternating series test fails, what tests can you use to conclude that the series diverges? I'm thinking nth term, p-series, geometric series, but i'm not sure...please help =]. A sample question that I am working on is...

the series (-1)^n 3^(n-2) / 2^n with n from 1 to infinity
p.s. there is a multiplication between the n and the 3

2007-09-26 13:00:53 · 2 answers · asked by V 2 in Mathematics

2007-09-26 12:58:26 · 13 answers · asked by Anonymous in Weather

a.) temperatures are moderate.
b) the density of the air is less
c) the air's sinking motion makes it hard for clouds to form
d) relative humidity is close to zero percent.


im guessing c.

10 points anyone??

2007-09-26 12:58:10 · 4 answers · asked by taylor mac 2 in Weather