Science & Mathematics - 12 September 2007

2007-09-12 18:13:31 · 1 answers · asked by uncleclover 5 in Physics

ok so ike we did this experiment when u have to watch the shadow of a circle until it moves a complete diameter. the time we got was 3:37 (minutes). and were supposed to assume that the moving one diameter is equal to .5 degrees.
the formula were supposed to use is time/.5 degrees x 360 degrees/1 rotation.
we ended up with 43.4. is that right? what did we do wrong?

and for linear speed, the equation is d/t = 2pi r /hours. the earth to sun distance is 149.6 x10 exponent 6 km. raduis of the earth is 638 x 10 exponent 3 km.

does anyone know how to do this?
thankkkss sooo much if u do.

2007-09-12 18:12:09 · 3 answers · asked by nikijoe46 3 in Physics

This is a math question. (blank) represents the missing answer

2007-09-12 18:07:56 · 5 answers · asked by VCA 1 in Mathematics

25 cm 2

Need immediate help, please.

A person that gives the best answer will get 10 points. :)

2007-09-12 18:07:18 · 2 answers · asked by madeinczech 5 in Mathematics

One of the freons, CCl2F2, is manufactured by reacting carbon tetrachloride with hydrogen fluoride. The other reaction product is hydrogen chloride. What is the yield of this reaction, if a manufacturer obtains 160 kg of CCl2F2 from 280 kg of CCl4? (Enter the yield in percent.)

2007-09-12 17:59:13 · 1 answers · asked by danz2289 1 in Chemistry

2007-09-12 17:58:51 · 2 answers · asked by Anonymous in Physics

2007-09-12 17:58:38 · 8 answers · asked by Christopher 2 in Astronomy & Space

Any help is appreciated =)

An ionic compound forms when calcium (Z=20) reacts with iodine (Z=53). If a sample of the compound contains 8.98×1019 calcium ions, how many iodide ions does it contain?

2007-09-12 17:55:44 · 1 answers · asked by Anonymous in Chemistry

Or are they just humans that have died?

2007-09-12 17:54:35 · 14 answers · asked by Life goes on... 6 in Paranormal Phenomena

2007-09-12 17:46:50 · 6 answers · asked by Cabt.man 1 in Weather

A river flows due south with a speed of 2.00m/s . A man steers a motorboat across the river; his velocity relative to the water is 4.20m/s due east. The river is 800m wide.
What is the magnitude of his velocity relative to the earth? What is the direction of his velocity relative to the earth? How much time is required for the man to cross the river?

2007-09-12 17:45:24 · 1 answers · asked by Anonymous in Physics

I have a Chemistry assignment and one of the questions are to write a balanced equation for my element, which is carbon.
What would be a balanced equation for carbon?

2007-09-12 17:44:36 · 2 answers · asked by hollow_stars 1 in Chemistry

Describe the preparation of 2 liters of 0.05 M ammonium choloride buffer, pH 9.4, starting with 1 M NH4OH and 2.13 M HCL.

2007-09-12 17:38:50 · 2 answers · asked by jon st. germain 1 in Chemistry

A particle moving along a straight line has position x meters at time t >0 seconds given by the formula: x=t^2-3t-1/t

Correct me if I'm wrong
v(t)= t^(-2) + 3t - 3
a(t)= -2t^(-3) + 2

My logic is that a particle will have maximum velocity when acceleration is 0 (So, the particle will not get faster). So, you set a(t)=0 and input the values of t into v(t) and the highest number is the maximum velocity. Is this logic correct?

2007-09-12 17:38:41 · 3 answers · asked by Jeff K 2 in Mathematics

2007-09-12 17:36:41 · 5 answers · asked by Christopher 2 in Astronomy & Space

Does somebody know how many time does it take to go too the moon?

2007-09-12 17:34:02 · 2 answers · asked by $$$Fabian$$$ 2 in Astronomy & Space

it says that you have to group...


b^2-9b-b+9=0...

2007-09-12 17:31:37 · 4 answers · asked by Jay-j 2 in Mathematics

I have to write a formula representing the least number of moves possible to move the disks in the Tower of Hanoi to the proper position. With 2 disks, 3 moves are required, 3 disks require 7 moves, 4 disks require 15 moves and 5 disks require 31 moves. How do I go about writing a formula where "n" equals the number of disks and come up with the number of moves required?

2007-09-12 17:29:57 · 3 answers · asked by moira77 4 in Mathematics

2007-09-12 17:26:30 · 16 answers · asked by engelfeurs 2 in Astronomy & Space

Atlantic ocean, indianocean,pacific ocean

2007-09-12 17:26:21 · 5 answers · asked by Anonymous in Earth Sciences & Geology

2007-09-12 17:25:45 · 8 answers · asked by d_mukherjee_2000 1 in Zoology

thank you ...

2007-09-12 17:25:30 · 1 answers · asked by azen 1 in Chemistry

If possible, provide a formula
Help? Please. :)

2007-09-12 17:24:37 · 3 answers · asked by Anonymous in Chemistry

thank youu...

2007-09-12 17:23:04 · 1 answers · asked by azen 1 in Chemistry

2007-09-12 17:23:00 · 16 answers · asked by d_mukherjee_2000 1 in Zoology

2007-09-12 17:21:08 · 7 answers · asked by d_mukherjee_2000 1 in Zoology

A fire is sighted from two ranger stations that are 5000m apart. The angles of observation to the fire measure 52 degrees from one station and 41 degrees from the other station. Find the distance along the line of sight to the fire from the closer of the two stations?

I tried doing this problem more than 5 times but I can't seem to get the right answer

2007-09-12 17:20:24 · 5 answers · asked by Anonymous in Mathematics

I am not entirely sure how it works. So, because of the difference of impedance b/t lets say a transmission line and a load creates a difference of voltage. To cross this voltage some of the energy of the signal is given up and the rest of the energy can't cross this distance and reflects back. I kinda don't get how the last part affects the signals. Is it just interference with the reflected waves when the incoming waves go through or does the energy loss across this potential effect the waveform.

Lets consider a 1,000 ohm source impedance, 50 ohm wire impedance, and 10,000,000 ohm oscilloscope impedance, which was used during class demonstration. The cable was connected where he put a resistor 50 ohm and a 50 ohm terminator to show reduction in the noise. Don't you apply the reflection coefficient to the source-cable junction and then scope-cable junction. I got for one (10M/50 -1 )/(10M/50-1) that would mean the cable is infinite and should not be much noise.

2007-09-12 17:20:21 · 2 answers · asked by Anonymous in Engineering

For the life of me I can't remember how to solve this all the way. I remember doing it but I can't think of it now. If someone would be so kind as to help me with these 2 problems and maybe explain how they did it, I would be very thankful!

Solve for x:

6x - 4/3 = 3/4x + 1/3

and

5(x+1) = 7x+3

2007-09-12 17:12:42 · 12 answers · asked by Vicki 3 in Mathematics

a(with arrow pointing to left on top)=(4.0m)i - (3.0m)j + (1.0m)k
b(with arrow pointing to left on top)=(-1.0m)i+(1.0m)j+(4.0m)k.

In unit-vector notation, find (a) a + b, (b) a - b and, (c) a third vector c such that a - b + c = 0.

Please explain with the answer so that i understand the process rather than just get the answer. Thanks! xoxo

2007-09-12 17:11:37 · 1 answers · asked by laureni 1 in Physics