Science & Mathematics - 12 February 2007

The copper wire used in a house has a cross-sectional area of 2.90 mm2. If 10.5 m of this wire is used to wire a circuit in the house at 20.0°C, find the resistance of the wire at the following temperatures.
(a) 30.0°C

(b) 10.0°C

2007-02-12 15:40:45 · 1 answers · asked by Anonymous in Physics

A certain conductor has 6.50 1028 free electrons per cubic meter, a cross-sectional area of 4.00 10-6 m2, and carries a current of 2.10 A. Find the drift speed of the electrons in the conductor.

2007-02-12 15:40:03 · 1 answers · asked by Anonymous in Physics

If a certain source emits radiation of wavelength 320. nm what is the energy, in kJ, of one mole of photons of this radiation?

2007-02-12 15:37:36 · 1 answers · asked by jeniferrrr 1 in Chemistry

The answer is 1/27x^3y^12 but i don't get it.
Shouldn't the Y cancel out? so it would be (3/x)^-3?
Can someone explain please?

2007-02-12 15:37:13 · 3 answers · asked by Anonymous in Mathematics

two cards are drawn from a standard deck with 52 playing cards without replacement . what is the probability of drawing a 2 followed by 5 ?

2007-02-12 15:36:17 · 2 answers · asked by Anonymous in Mathematics

tell me why because i don't know because i am still a kid.

2007-02-12 15:35:49 · 13 answers · asked by fReDs526 3 in Astronomy & Space

I am writing a story in which the principal character regularly handles dead bodies. Part of the plot premise depends on trying to alter the course of chemical changes the body goes through in the first weeks after death. But my college physiology courses were kind of hit-or-miss on post-mortem issues. If you have any books, links, or information about the changes the human body goes through in the first fourteen days after death I would be very appreciative and you would get ten extra points!

2007-02-12 15:35:27 · 0 answers · asked by nbsandiego 4 in Biology

A red number cube and blue number cube are rolled . What's the probability of the red cude showing a 3 and the blue cibe showing a 6 .

2007-02-12 15:33:31 · 5 answers · asked by Anonymous in Mathematics

2007-02-12 15:33:30 · 2 answers · asked by Anonymous in Medicine

2007-02-12 15:33:29 · 6 answers · asked by webelieve04 2 in Weather

if 2 cars are leaving a intersection, and one is moving at 20 mph south and the other is moving 36 mph west. How fast is there distance changing the instant they are 2.4 miles away?

2007-02-12 15:33:02 · 3 answers · asked by SUPERMAN 4 in Mathematics

solve for x:

(2x – 5)/3 – 3/2 = (x + 4)/5

2007-02-12 15:32:10 · 2 answers · asked by Brackish 1 in Mathematics

pennies.How many quarters, dimes and pennies are there respectively?

2007-02-12 15:31:13 · 2 answers · asked by k19widowmaker 1 in Mathematics

I can not figure out this problem:

"A uniformly dense rope of length "b" and mass density "u" (mu, but u will work) is coiled on a smooth table. One end is lifted by hand with aconstant velocity "v". Find the force of the rope held by the hand when the rope is a distance "a" above the table (b>a). "

I just said that F(a) = u*a*g but apparently the answer is u*a*g*(1+v^2/(a*g))

2007-02-12 15:30:43 · 2 answers · asked by Goose 2 in Physics

Calculate ( 1 + i ) ^ 2. Use your result to find two square roots of "i"

2007-02-12 15:28:44 · 4 answers · asked by brwnsugar2spice 1 in Mathematics

i learned in science today that the equation E=MC^2 means that matter can be converted into energy. does this also mean that theoretically you could convert energy into matter as well? and if so how would you do this?

2007-02-12 15:27:59 · 10 answers · asked by Anonymous in Physics

what are their function ?how it works ?

2007-02-12 15:26:03 · 4 answers · asked by Anonymous in Physics

Imagine yourself meeting a person who seems very reasonable and cultured. You'd naturally think that whatever this person says is a reflection of the culture and intelligence you assume him to have. But when he begins to speak, even though you perceive no other change in his reasonable demeanor, he startles you with his incredible nonsense. He may insist that white is just a lighter shade of black, for example, or claim that the clouds in the sky are simply huge bunches of cotton. He believes things that no reasonable person with normal awareness and judgment could believe. He claims it is raining even though the sun is shining; and if you take him outside and show him the evident sunlight, still he persists in his claim that rain is falling and he even declares that he's getting wet! If you saw such a person, you could describe him in several ways. You might say he was being illogical, deluded, or even that he'd lost his mind, or even that he was crazy.

2007-02-12 15:25:13 · 16 answers · asked by S_M 1 in Biology

Troy does yard work for some of his neighbors, earning $25 for mowing lawns and $40 for "the works," which includes mowing, trimming, and weeding. If in one 3-week period Troy earned $370, how many yards did he mow and how many yards got "the works"?

2007-02-12 15:25:03 · 4 answers · asked by Mike H 2 in Mathematics

i don't know how to solve this problem:

The area of a triangle is 384 cm.sq. Its base is 3 times the height, find the base and the height.

you dont have to do the problem for me but, can you help me go about solving it? thanks SOO much!

2007-02-12 15:20:40 · 5 answers · asked by okay. 2 in Mathematics

2007-02-12 15:19:10 · 3 answers · asked by Anonymous in Geography

1) x^2+1/x^2-1 = 2/x-1 + x/x+1

2) 1/x-1 + x/3 = x/x-1

2007-02-12 15:18:59 · 1 answers · asked by Anonymous in Mathematics

if a deck of cards numbered from 1 to 10 is used , what are the odds of randomly drawing a card whose value is a multiple of three?

2007-02-12 15:18:48 · 5 answers · asked by Anonymous in Mathematics

I learn this in High School and now its stuck in head looking for that formula, I know the answer is 5500 or is it 5550?

2007-02-12 15:18:38 · 5 answers · asked by Gina h 1 in Mathematics

The boiling point and freezing point of benzene are 80.1°C and 5.5°C, respectively.)
boiling point

2007-02-12 15:18:32 · 1 answers · asked by chance w 1 in Chemistry

it has 5 letters.
another Qs is: a.k.a. Electron-dot structures?
it also made up w/ 5 letters.

2007-02-12 15:18:28 · 1 answers · asked by Girl 1 in Chemistry

tell me like weather in wichita for today ?

2007-02-12 15:17:21 · 4 answers · asked by wether kid 1 in Weather

A Divergent Oceanic/Oceanic Boundary, A Divergent Continental/Continental Boundary, A Divergent Oceanic/Continental Boundary (Subduction Zone), and A Hot Spot

2007-02-12 15:17:09 · 2 answers · asked by Neannee, Superwoman, Mz Jones 1 in Earth Sciences & Geology

(a) 14.2 g of sucrose (C12H22O11) in 686 g of water
m
(b) 7.04 moles of ethylene glycol (C2H6O2) in 3676 g of water
m

2007-02-12 15:16:45 · 1 answers · asked by chance w 1 in Chemistry

Solve the inequalities

2007-02-12 15:14:42 · 5 answers · asked by Anonymous in Mathematics