Science & Mathematics - 18 August 2007

The sum of two numbers is 35. Their difference is 11. What are the two numbers?
Solve the system by substitution.
3x – y = –7
x + y = –9
did everything else on homework....just need help with these..

2007-08-18 10:37:23 · 7 answers · asked by Anonymous in Mathematics

I've notcied this happening when i see someone yawn and then i have the sudden urge to yawn as well. And vice versa, if someone sees me yawning they yawn too. Why does this happen? Is there a connection?

2007-08-18 10:29:52 · 3 answers · asked by sportbest 2 in Medicine

Where has our summer gone? We live in North Lincolnshire which has been severely affected by the floods of July and now. It's now pelting it down again and it has done all day. We haven't been given any sandbags but having said that, our road hasn't suffered badly.
However, on our way home from work, it was obvious that that the hotspots from last month are building up again.
What's going on in your neck of the woods?

2007-08-18 10:27:17 · 9 answers · asked by Zoe S 3 in Weather

If so, what happens?

2007-08-18 10:25:24 · 8 answers · asked by Anonymous in Physics

we thought it was a locust, but its not, its large and black and yellow striped on its abdomen and about 5 inches long, is it some kind of burrowing or mining bee?? e mail me crackecody@yahoo.com. thanks.

2007-08-18 10:21:45 · 4 answers · asked by Anonymous in Zoology

Quickly Please

2007-08-18 10:17:42 · 8 answers · asked by SOfTbAll CHiCky_12 2 in Mathematics

I'm going to be doing some experimenting with a small portable ultrasonic welder I am purchasing from asia. I understand that it probably won't comply with local standards so I am going to get an electrical engineer to look over it, to see if its safe to use. However my main concern is the output to the transducer. I've been told that ultrasonic welders can run as high as 3000volts through the output. I am worried that because of this high voltage, it may be dangerous for me to handhold the transducer. I understand that this is a question that I should also put to the engineer and I will ask this. In the short term however, I was wondering if anyone would be able to tell me approximately at what power level/ voltage combination, electricity becomes dangerous?

2007-08-18 10:13:37 · 9 answers · asked by Anonymous in Engineering

These things are confusing.

Can someone answer these questions?

1. Using two different instruments, I measured the length of my foot to be 27cm and 27.00cm. Explain the difference between these two measurements.

2. I can lift a 20kg weight over my head ten times before i get tired. write this measurement to the correct number of significant figures.

3. Why are there 3 sigfigs in 5.40 and only 1 in 3000?

I'd like to know WHY for these questions, too. im kinda confused....actually really confused. thanks.

2007-08-18 10:12:33 · 10 answers · asked by Anonymous in Mathematics

What is a sea monkey aerator? Where can I get one? How much do they cost? Is there anything that I can use instead of one? And lastly do I need one?

2007-08-18 10:11:54 · 1 answers · asked by ☮ tree hugger ☮ 3 in Zoology

the possible answers are n to 6th power - 3n to 5th power + 6n squared + 12, 15n to 7th power, nto 6th power - 3n to 5th power + 17n squared + 48, or n to 6th power - 3n to 5th power + 6n squared +48. I know this sounds difficult; but I am typing and it is hard to take a number to a certain power. I am not sure what key to hit. If there is any answer to this problem and if anyone can help me with squaring on a computer or to a certain power, I would appreciate it. Thank you

2007-08-18 10:09:18 · 4 answers · asked by carole bostic 1 in Mathematics

why are they esrthquakes on the air is there any website that tells you that or you know somethin

2007-08-18 10:02:04 · 2 answers · asked by Anonymous in Earth Sciences & Geology

ok I have a few dark green rocks that I really think are emeralds. What kind of person would I go see to help me find out?

2007-08-18 09:58:26 · 5 answers · asked by lil_sis458 2 in Earth Sciences & Geology

2007-08-18 09:57:07 · 13 answers · asked by awesome_jarrett7 2 in Mathematics

Time dilation is the phenomenon whereby an observer finds that another's clock which is physically identical to their own is ticking at a slower rate as measured by their own clock. This is often taken to mean that time has "slowed down" for the other clock, but that is only true in the context of the observer's frame of reference. Locally, time is always passing at the same rate. The time dilation phenomenon applies to any process that manifests change over time.

I would like to understand why this occurs...not just the phenomenon itself.

2007-08-18 09:55:05 · 5 answers · asked by Gary 1 in Physics

f(x) x^2+x-6 Solve F(x) > 0

X^2-3x+2x-6
X(X-3)+2(x-3)
(x+2)(X-3)

X E (-oo,-3)U(2,oo)

So my question is why is it -3 and 2 instead of -2 and 3. when it is -2 or 3 that would make (x+2)(X-3)=0

2007-08-18 09:54:04 · 3 answers · asked by roguetrader12002 4 in Mathematics

2007-08-18 09:53:19 · 2 answers · asked by furqan a 1 in Engineering

2007-08-18 09:51:22 · 7 answers · asked by Anonymous in Physics

the sum of three consecutive odd integers is 57 what are the integers????

How would i find the inverse function of f(x)=3x-4
is the inverse a function and why?\

what is the remainder when you divide (x^3+2x+1) by (x-3)

2007-08-18 09:49:34 · 4 answers · asked by Anonymous in Mathematics

please show me how to work this problem

2007-08-18 09:48:07 · 4 answers · asked by Anonymous in Mathematics

2007-08-18 09:45:34 · 4 answers · asked by john 1 in Other - Science

hypothetically speaking which other planet would be the least non hospitable in your views

2007-08-18 09:44:18 · 11 answers · asked by ? 2 in Astronomy & Space

2007-08-18 09:44:12 · 3 answers · asked by gili192 1 in Weather

Find:

f(x+Δx) - f(x) / Δx if f(x)= 8x^2+1

2007-08-18 09:40:19 · 6 answers · asked by NEpatriots12 2 in Mathematics

Chairs are [obviously] designed to be sat on, where as tables are designed to be sat at. Why then, is it the case that tables are more comfortable for sitting on than chairs?

2007-08-18 09:39:38 · 16 answers · asked by Anonymous in Other - Science

also not sure on these....
An employee who produces x units per hour earns an hourly wage of y = 0.50x + 11 (in dollars). Find the hourly wage for an employee who produces 11 units per hour.
find the slope of the line passing through the points (-7, 4) and (8,4)
find the slope of (0,3)

2007-08-18 09:34:02 · 6 answers · asked by Anonymous in Mathematics

the trinomial is 3x ²– 5x + 2
i keep getting the answer (2x+3)(x+1) but when i multiply it out to check i always get 2x ² +5x+3
help?

2007-08-18 09:28:23 · 8 answers · asked by Izzie 2 in Mathematics

would like to be kept up to date on "legitmate" ufo sitings in the rual st louis area

2007-08-18 09:23:27 · 6 answers · asked by mdloco77 1 in Astronomy & Space

We are all keenly aware of Global Warming and the dire consequences it is having on Mother Earth. With melting icecaps, retreating glaciers, rising sea levels, more violent storms and hurricanes, and generally a temperature that rises exponentially; we are inevitably in a similar position as the occupants of train that is speeding its way off a cliff, bringing all life on Earth together with us unless something drastic is done or takes place to reverse the trend. We know what needs to be done, but as we stand today, we are lacking the will and the unity to make necessary sacrifices. Scientific models show that if the trend continues, life on earth may be wiped out before the end of the century. Does this mean that the train will hurtle off the cliff in a few generations' time? What do you think?

2007-08-18 09:23:04 · 20 answers · asked by ? 2 in Weather

Please explain your answer and 1 quart is equal to 0.9464L.

2007-08-18 09:19:22 · 8 answers · asked by Troy B 4 in Chemistry

I have a standard transformer with 7 wires:
2 black
2 red
2 yellow
1 red/yellow striped

What connections do these wires correspond to?
That is, which should connect internally to the primary coil, the secondary coil, and coil-taps (based on the number of wires, I assume that the secondary coil is tapped).

I must determine this in order to connect the wires (externally) appropriately.

Any help is greatly appreciated!

2007-08-18 09:12:41 · 9 answers · asked by Not Eddie Money 3 in Engineering