Science & Mathematics - 18 September 2007

Express the area A of this cross section as a function of the diameter D (in cm) of the circular part

2007-09-18 11:52:16 · 1 answers · asked by ohoma 1 in Engineering

Aluminum is placed in Copper (II) chloride. The products are copper and aluminum chloride. is the aluminum chloride a supernate (liquid solution) or is it a precipitate (solid)?

2007-09-18 11:51:06 · 5 answers · asked by ♠Jay♠ 5 in Chemistry

2007-09-18 11:49:45 · 1 answers · asked by Sunny Side Up 1 in Biology

find all solutions x1, x2, x3 of the equation vector b= (x1 times vector v1) + (x2 times vector 2) + (x3 times vector 3) where

vector b=
{-8}
{-1}
{2}
{15}

vector 1=
{1}
{4}
{7}
{5}

vector 2=
{2}
{5}
{8}
{3}

and vector 3=
{4}
{6}
{9}
{1}

I know these vectors can be simplied to the following equations, but i do not know how to solve 3 variables with 4 equations:

x1 + 2 x2 + 4 x3 = -8
4 x1 + 5 x2 + 6 x3 = -1
7 x1 + 8 x2 + 9 x3 = 2
5 x1 + 3 x2 + 3 x3 = 15

ANY HELP WOULD BE GREATLY APPRECIATED

2007-09-18 11:48:37 · 1 answers · asked by MARK 2 in Mathematics

Joe is trying to pick up Ryan who is waiting directly across the river. Joe heads straight across the river in his kayak at a velocity of 5 kilometers per hour, but the river current flowing at 5.2 kilometers per hour pushes him downstream. The actual velocity of his kayak is 7.21 Km/h.

If it takes Joe 25.2 seconds to cross the river, how far downstream (in meters) does Ryan have to walk to get in the boat?

2007-09-18 11:46:03 · 1 answers · asked by Brian 4 in Physics

2007-09-18 11:45:52 · 1 answers · asked by Sarah M 1 in Chemistry

An object is thrown directly upward from the ground. After t seconds its distance in ft. above the ground is s = 144t-16t^2.

a) After how many seconds is the object 128 ft. above ground?
b) Afer how many seconds does the object strike the ground?

Please show work. 10 pts. for best answer.

2007-09-18 11:43:17 · 5 answers · asked by TypeA 5 in Mathematics

thanks for all and any anwer

2007-09-18 11:43:13 · 5 answers · asked by Anonymous in Medicine

2007-09-18 11:37:53 · 3 answers · asked by Anonymous in Other - Science

160m below. how many seconds before the plane is directly overhead should the supplies be dropped?

2007-09-18 11:36:28 · 1 answers · asked by ? 1 in Physics

...then why is it never over, and why is it always in the same location in every photo you see of Jupiter? Shouldn't it move off gradually like storms here?

2007-09-18 11:34:33 · 6 answers · asked by monemarcos 1 in Astronomy & Space

think about thier strenght!!

2007-09-18 11:34:09 · 6 answers · asked by Eagle 1 in Zoology

do you know what the subscript and superscripts represents in isotopes?

2007-09-18 11:33:23 · 1 answers · asked by Anonymous in Chemistry

calculate a) the distance the car coasts before it stops, b) the time it takes to stop

2007-09-18 11:32:01 · 1 answers · asked by ? 1 in Physics

2007-09-18 11:30:07 · 16 answers · asked by Anonymous in Astronomy & Space

They have "faith" in the astrologer's ability to predict events based on the positions of celestial objects. What is your reaction to this "faith/it works for me" argument?

2007-09-18 11:29:38 · 6 answers · asked by Anonymous in Astronomy & Space

answer please

2007-09-18 11:29:14 · 3 answers · asked by Anonymous in Biology

2007-09-18 11:28:56 · 2 answers · asked by TIARA T 1 in Botany

The space shuttle orbits the Earth at a speed of 8.1 km/s. If it were possible to fly the space shuttle at this velocity to the nearest star to the sun, calculate how many years would be required for the trip (one way). The sun is 1.3 parasecs distant, where 1 parsec=3.26 light years (a light year is the distance light travels in one year), and the speed of light is 3.00x10^8m/s.



I'm quite confused on how to do this problem. Can someone help me please!!!! :) Thank You!

2007-09-18 11:25:57 · 4 answers · asked by Natlsn12009 1 in Mathematics

like as is the rule for dividing 1001

2007-09-18 11:24:37 · 3 answers · asked by dorothy_diamond 1 in Mathematics

2007-09-18 11:24:16 · 2 answers · asked by Wolfie 2 in Biology

i need 2 know 4 science class!!!

2007-09-18 11:23:12 · 1 answers · asked by l♥ve143~♥~♥~♥ 2 in Physics

does anyone know the answers to these?

Given a fundamental of 125 Hz which of the following set of frequencies (from the sound spectrum) will most likely add to a strong sense of musical pitch in the fundamental?
a. 200 Hz
b. 500 Hz
c. 400 Hz
d. 250 Hz

Given a fundamental of 125 Hz, which of the following set of frequencies (from the sound spectrum) will most likely detract from a strong sense of musical pitch in the fundamental?
a. 250 Hz
b. 500 Hz
c. 375 Hz
d. 200 Hz

2007-09-18 11:20:19 · 1 answers · asked by JoAnna 2 in Physics

Think of the number!

2007-09-18 11:20:18 · 18 answers · asked by smileyhippo2423 2 in Mathematics

2007-09-18 11:17:18 · 7 answers · asked by vgl_13 1 in Mathematics

It would have a limited threaded section, and the smooth, socket side protrudes. I want to use the exposed part as a side-bearing surface, in a narrow channel where a regular cap screw head would be of too great a diameter. In that sense it would not serve the traditional purpose as a set screw, so it may have a different name. References appreciated.

2007-09-18 11:16:18 · 2 answers · asked by Jdude 2 in Engineering

i am impaired when it comes to math..my teacher asked us to do these practice problems but i have no idea how to find the answer to these can someone help me figure it out??

1) a tuning fork has a frequency of 343 Hz. asecond tuning fork is struck and a student notices a beat frequency of 3 Hz. what are two possible values of the second tuning fork??

2) the middle "C" has a frequency of 256 Hz and a wavelength of 1.3 meters. how fast does this sound travel.

2007-09-18 11:15:03 · 1 answers · asked by molly 1 in Physics

2007-09-18 11:13:34 · 6 answers · asked by dmciscool2007 2 in Engineering

2007-09-18 11:09:43 · 1 answers · asked by Mr. Smith 5 in Astronomy & Space

2007-09-18 11:09:09 · 2 answers · asked by Anonymous in Biology