Science & Mathematics - 23 July 2007

i have seen in texts that we al;ways use sin wave to represent a AM modulated wave why dont we use a cosine wave or tangetial wave to do so

2007-07-23 04:07:13 · 4 answers · asked by dhanvanthari m 1 in Engineering

determine whether lines are perpendicular lines

2007-07-23 04:06:05 · 5 answers · asked by bee 1 in Mathematics

2007-07-23 04:03:27 · 5 answers · asked by Anonymous in Mathematics

i need this urgently for my science project . please help out !

okay basically , we have to describe a phenomena. in this case, its when i lean my left foot and left shoulder against a wall , i am unable to lift up my right foot . try it . you really cant .
i need the concept behind it , but i cant find it anywhere . really need help . if you know anything or hv any websites to recommend, please tell me ! THANKS .
btw, some examples of the concept : centre of gravity . when i lean against the wall my centre of gravity is not balanced . thus , blablabla . something lik that .

2007-07-23 04:02:08 · 6 answers · asked by Anonymous in Physics

If the original population has a positively skewed distribution, the distribution of sample means for that population, with N = 100 for each sample, will have a positively skewed distribution

2007-07-23 03:58:50 · 3 answers · asked by Anonymous in Mathematics

means? True or False?

2007-07-23 03:57:39 · 1 answers · asked by Anonymous in Mathematics

2007-07-23 03:55:32 · 3 answers · asked by Alex D 1 in Biology

((24g-144)/(g^2-2g-24)) * ((g^2-3g-28)/(4g-28))

2007-07-23 03:53:31 · 2 answers · asked by just me 1 in Mathematics

It is given that y = 3x^p^2 - 5p + 7.

Q1) Find the value of x when p = 1 and y = 81.
Q2) If y varies directly as x, find the possible values of p.

Solve these questions correct with detailed workings and earn points!!! :)
The lucky person with the best answer will be voted as the "BEST ANSWER".
Voting of the best answer will take place after 12hours!!.

2007-07-23 03:51:59 · 2 answers · asked by Anonymous in Mathematics

I need to find a relatively cost effective way to measure the wavelength of red LED lights. I need to test several to find their wavelength range, then purchase more red LEDs, and measure them so I can keep the ones that fall within my wavelength range, and discard the others. This is for a machine that picks up red light from a relatively specific range, and the LEDs on it currently have lost strength (many are from the early 90s, some even older). I need to replace the existing LEDs with others of compatible wavelength. Also, in keeping with my explanation, red LEDs with weakened strength would still have the same wavelength light, but less intensity, correct? Thank you very much to anyone who can help me out with this!

2007-07-23 03:47:56 · 2 answers · asked by Zach F 1 in Other - Science

2x^2+3x+1= (2x+1)(x+1)

2007-07-23 03:45:06 · 6 answers · asked by just me 1 in Mathematics

y^3+5y^2-9y-45

2007-07-23 03:43:49 · 1 answers · asked by just me 1 in Mathematics

A car accelerated from 6.00 m/s to 20.0 m/s, over a distance of 50 m. What is the rate of acceleration??

2007-07-23 03:38:20 · 3 answers · asked by Leah B 1 in Physics

If you use a current limiting resistor, it will get extremely hot, and will waste energy. By using a capacitor, no heat is dissipated in the capacitor. My question is, how much electricity will I use? To get 20mA through the LED, surely I am going to use 20mA at 110V. So where does the energy go?
And can someone offer a calculation for the capacitance to run a 2v 20mA LED. Thanks.

2007-07-23 03:37:32 · 2 answers · asked by Experimentor 2 in Physics

If the equation 2x^2+4x=-3 is being solved, is -1+or-1/2i√2 the answer? If this is not the answer, showing me what the correct answer is and how to get that answer will be very helpful. Thank you, in advance also.

2007-07-23 03:34:28 · 2 answers · asked by jumba 1 in Mathematics

im really confused, pls. gve me some infos

2007-07-23 03:32:50 · 11 answers · asked by cpt. siopao 1 in Astronomy & Space

ok last night i was at my friends house we were having a bomb fire and i looked up in the sky and saw this red light up there it was pretty big and it seemed to be close like the height a plane would fly, well i didnt think nething of it at first i just thought it was one of those red tower lights but then it looked like it moved to the right a little bit then i said something and we all watched it it stayed in the same spot, it looked kind of like it was blinking or flashing just a little bit tho not alot, well it just sat there i took my cell phone out and recorded it but its not that good of a recording but any way it stayed in the same spot just a big red light still, and then all of the sudden it just dropped straight down not sideways like a shooting star would drop but straight down and it disapeared???? is there any logical explanaition???????

2007-07-23 03:32:23 · 7 answers · asked by Anonymous in Astronomy & Space

2007-07-23 03:31:58 · 3 answers · asked by Anonymous in Chemistry

Is it possible to produce a white guinea pig by crossing a homozygous black guinea pig and a heterozygous black guinea pig?

2007-07-23 03:31:16 · 3 answers · asked by Alex D 1 in Biology

1)The ideal surface area of a rubber ball shipped from the factory is 50.25 square inches. The company inspector insists that the balls shipped vary no more than 0.3 square inches of this total. To the nearest hundredth, what is the minimum value for the surface area of rubber balls shipped?
50.25
49.95
50.55
none of these
2) State the possible number of imaginary zeros of f(x) = 10x3 - 4x2 + 2x - 6
exactly 1
exactly 3
3 or 1
2 or 0
3)Which describes the number and type of roots of the equation x3 - 4x2 + 50x + 7= 0?
1 positive, 2 negative
2 positive, 1 negative
3 negative
3 positive
4) Solve for x in 12=-1/7(-42x+21)
2/5
2/3
3/2
5/2

I really appreciate all your help, but the best will get the ~~~BEST ANSWER~~~!

2007-07-23 03:26:43 · 3 answers · asked by Anonymous in Mathematics

The total number of longitudes?

2007-07-23 03:26:01 · 3 answers · asked by prcool 1 in Geography

We are on vacation in TN and keep seeing these moltings all over the place! I was wondering what the insect was? Here is a link to a picture I took of the shedding! http://s50.photobucket.com/albums/f315/krystalstreet/?action=view¤t=DSC02657.jpg THANKS!!

2007-07-23 03:25:06 · 8 answers · asked by kasjar 1 in Zoology

((6d-36)/(d^2-3d-18)) / ((3d-21)/(d^2-4d-21))

2007-07-23 03:23:22 · 1 answers · asked by Monkey Kick 1 in Mathematics

((3p^3x)/(-6y^3)) / ((15p^9)/(-6y^5)

2007-07-23 03:22:07 · 1 answers · asked by Monkey Kick 1 in Mathematics

((24g-144)/(g^2-2g-24)) * ((g^2-3g-28)/(4g-28))

2007-07-23 03:20:57 · 2 answers · asked by Monkey Kick 1 in Mathematics

i'm undertaking a study on zirconia nanoparticles, and i need help understanding alot of the concepts

can anyone recommend some books/online references that are useful in the areas of ceramics, nanoparticles, solid state physics, etc.

thanks alot

2007-07-23 03:20:52 · 1 answers · asked by Sean | 2 in Engineering

2007-07-23 03:20:04 · 2 answers · asked by captbullshot 5 in Engineering

((m^3+m)/(2) * ((4)/(m^2+m))

2007-07-23 03:19:21 · 2 answers · asked by whatever 1 in Mathematics

What characteristics of microwaves determine which dishes can be used safely as microwave-ware, and which not?

2007-07-23 03:19:17 · 7 answers · asked by Sudeep 3 in Engineering

it has that very specific warning label on it. why ? what would happen?

2007-07-23 03:14:37 · 12 answers · asked by bbq 6 in Medicine