Science & Mathematics - 4 December 2007

1. Elvin drove halfway from Ashton to Dover at 40 mi/h and the rest of the way at 60 mi/h. What was his average speed for the whole trip? (hint: let the distance for the whole trip be, say, 100 mi.)


2. A train averaged 120 km/h for the first two thirds of a trip and 100 km/h for the whole trip. Find its average speed for the last third of the trip.


3. Pipe A can fill a tank in 5 hours. Pipe B can fill it in 2 hours less time than it takes pipe C, a drainpipe, to empty the tank. With all three pipes open, it takes 3 hours to fill the tank. How long would it take pipe C to empty it?

2007-12-04 08:53:20 · 3 answers · asked by Anonymous in Mathematics

is it everest?

2007-12-04 08:52:48 · 20 answers · asked by Anonymous in Geography

Ariana took 2 h longer to drive 360 mi. on the first day of a trip than she took 270 mi. on the second day. If her speed was the same on both days, what was the driving time each day?

2007-12-04 08:52:19 · 3 answers · asked by God Bless America!~ 4 in Mathematics

what Y is a river in scotland and a plant.

2007-12-04 08:51:42 · 4 answers · asked by Anonymous in Botany

I just dont know what the a and b are....
help?

2007-12-04 08:49:43 · 3 answers · asked by jo l 1 in Mathematics

a 150 newton bird feeder is supported by three cables . the cable is 30-60-90. find the tension in each cable.

2007-12-04 08:49:36 · 1 answers · asked by Don 1 in Physics

with two dice

2007-12-04 08:44:54 · 3 answers · asked by Nikhil R 1 in Mathematics

Find the length of the chord EF

2007-12-04 08:43:58 · 1 answers · asked by Anonymous in Mathematics

Ok I have a 45-45-90 triangle and I need to find the perimeter of it. I understand that you have to add all of the sides up to get the perimeter,but I need my answer in simple radical form and I dont understand how to add these radicals together. The two legs are radical(2) and the hyp is 2. Plz help!!!

2007-12-04 08:42:48 · 3 answers · asked by lusius188 1 in Mathematics

1. why does the height of a cumulus cloud base change from day to day?

2. what would happen to the height of a cloud base id the dewpoint temperature was lower?

3. how would it be possibel to have a day without any clouds?

4. what relationship would you expect to find between the air temp and the dewpoint temp at ground level if the area is covered by fog?

5. what happens to the air temp of a descending mass of air?

6. what happens to the dewpoint temp of a descending mass of air?

7. explain why a descending mass of air would become drier.

8. descirbe how you can determine the base altitude at which clouds form.


PLEASE HELP- I DO NOT UNDERSTAND! THX

2007-12-04 08:42:38 · 3 answers · asked by Anonymous in Weather

2007-12-04 08:42:07 · 7 answers · asked by Anonymous in Earth Sciences & Geology

x-(-2x -2) + 3 = 3x+ 9

2007-12-04 08:40:06 · 6 answers · asked by Anonymous in Mathematics

2007-12-04 08:38:27 · 4 answers · asked by Black Rose 2 in Physics

the big numbers are exponents. Thanks

2007-12-04 08:36:51 · 6 answers · asked by Anonymous in Mathematics

A 20.0 kg child slides down a 4.00 m-high playground slide. She starts from rest, and her speed at the bottom is 2.10 m/s.

What is the change in the thermal energy of the slide and the seat of her pants (in Joules)?

2007-12-04 08:36:47 · 1 answers · asked by Anonymous in Physics

give a good reason for best answer

2007-12-04 08:36:20 · 15 answers · asked by bubblebomb 2 in Zoology

2.Suppose an electric field with a magnitude of 2.8 E 4 N/C at a certain location, points due south. If a charge of -4.0 E -6 C is brought to the location, what is the electrostatic force that acts on this charge?

1.Matt forgot to put the fabric softener in the wash. As his socks tumbled in the dryer, they became charged. If a small piece of lint with a charge of +1.25 E -19 C is attracted to the socks by a force of 3.0 E -9 N, what is the magnitude of the electric field at this location?

2007-12-04 08:35:08 · 1 answers · asked by Goddess Allure 2 in Physics

Just for fun since I have nothing to do today, I want you to write a system of equations to solve this puzzle, and solve by using substitution.

If four times the larger number is added to two times the smaller number, the result is 14. When the larger number is reduced by two times the smaller number, the difference is 1. What are the numbers?

Good luck. (:

2007-12-04 08:34:27 · 12 answers · asked by rykster22 1 in Mathematics

last night I got my telescope out and was thinking I was looking at one thing and checked to see what I was seeing and it was a binary star....well duh, that was dumb

have you ever set your telescope to look at one thing and been totally baffled when the image you saw did not equal what you were expecting. the seeing was excellant for the first time in weeks last night!

2007-12-04 08:34:23 · 11 answers · asked by magnetic_azimuth 6 in Astronomy & Space

m and n are positive integers, such that n ≤ m. Prove that:
2^n * n! ≤ (m + n)! / (m - n)! ≤ (m^2 + m)^n

Please answer this problem with work and reasoning for what you did.

Thanks!

And does this problem require combinations in order for the inequality to be proved?

2007-12-04 08:30:58 · 2 answers · asked by UnknownD 6 in Mathematics

given: Butane (C4H10) has a heat of vaporization of 22.44 kJ/mol and a normal boiling point of -0.4 degrees celsius. A 250 mL sealed flask contains 0.55g of butane at - 22 degrees celsius.
How much butane is present as a liquid?
I got 0.25g

so I can't do the next question...
If the butane is warmed to 25 C , how much is present as a liquid?

2007-12-04 08:30:39 · 3 answers · asked by Pooh 4 in Chemistry

2007-12-04 08:29:39 · 41 answers · asked by Anonymous in Biology

Can anyone give me a link to a picture of a plant from this class?

2007-12-04 08:28:30 · 2 answers · asked by Zach D 2 in Botany

M= Mercury
V= Venus
E= Earth
M= Mars
C= Ceres
J= Jupiter
S= Saturn
U= Uranus
N= Neptune
P= Pluto
E= Eris

2007-12-04 08:27:02 · 3 answers · asked by Br0wnB0i4ShiZzLe 3 in Astronomy & Space

The human body obtains 970 KJ of energy from a candy bar.
If this energy were used to vaporize water at 100.0 C , how much water (in liters) could be vaporized? (Assume the density of water is 1.00g/mL .)

2007-12-04 08:26:51 · 1 answers · asked by Pooh 4 in Chemistry

voiding cytography
cbc(blood test)
liver enzymes
plasma glucose
western blot test
homoglobin
radioactive iodine uptake
cmv elisa antibody
bacterial culture
fungal culture
tuberculin test
coronary angiography
dna test
ana test

2007-12-04 08:22:18 · 2 answers · asked by chelsea b 1 in Medicine

2007-12-04 08:21:50 · 7 answers · asked by sheltonj2406 3 in Zoology

voiding cytography
cbc(blood test)
liver enzymes
plasma glucose
western blot test
homoglobin
radioactive iodine uptake
cmv elisa antibody
bacterial culture
fungal culture
tuberculin test
coronary angiography
dna test
ana test

2007-12-04 08:21:42 · 1 answers · asked by chelsea b 1 in Medicine

2007-12-04 08:20:55 · 10 answers · asked by dylan n 1 in Astronomy & Space

Yes, that's right, you. :D

I would really appreciate it if you could tell me how to do this Algebra problem. Don't just give me the answer, but explain/show your work. I would really appreciate it, and 10 pts. to the fastest best answer!:

(3x + 2)^6

<3

2007-12-04 08:19:35 · 6 answers · asked by isabelle.the.insomniac 2 in Mathematics