Science & Mathematics - 23 October 2006

2006-10-23 15:36:53 · 4 answers · asked by Metallica 1 in Biology

1. a radioisotope has a half life of 4 days. How much of a 20 gram sample of this radioisotope remains at the end of each time period.
a. 4 days
b. 8 days
2. the mass of cobalt-60 in a sample is found to have decreased from 0.800 g to 0.200 g in a period of 10.5 years. From this info calculate the half life of cobalt-60

please answer these, i really need help

2006-10-23 15:35:08 · 4 answers · asked by BlahBlahBlah 3 in Chemistry

when there's a fire and smoke is present, why is it nessassary to stay low? is it because something's density is less than air's so it rises up? it should be carbon dioxide, but co2 is more dense than air. so why?

2006-10-23 15:34:54 · 9 answers · asked by Anonymous in Other - Science

2006-10-23 15:32:40 · 12 answers · asked by Anonymous in Other - Science

2006-10-23 15:31:08 · 4 answers · asked by papasmurf 1 in Earth Sciences & Geology

2006-10-23 15:29:18 · 3 answers · asked by Somebody 2 in Mathematics

Step by step PLEASE...

2006-10-23 15:27:20 · 6 answers · asked by Anonymous in Mathematics

2006-10-23 15:23:35 · 2 answers · asked by rohit_gupta322 2 in Physics

(this is my last question for tonight) (I think it is a dam..about 80miles by 80miles at the edge of the polar ice cap)

2006-10-23 15:21:40 · 4 answers · asked by M 2 in Astronomy & Space

2006-10-23 15:19:24 · 8 answers · asked by Somebody 2 in Mathematics

i really need help with this question...does ne one know where there are 3 locations ne where in the world where there population is shrinking??and why?? please i really need help with this one question....thank u..

2006-10-23 15:15:11 · 5 answers · asked by Anonymous in Biology

Specifically, do they swim against strong currents? Rapids? Occasionally breach the water to jump over obstructions and small waterfalls?

2006-10-23 15:15:04 · 11 answers · asked by Marco S 1 in Zoology

I have been trying to figure this one out with a friend for about 3 days. We think we know the answer, but not sure how to get it mathematically

Find the point on the curve y=x^3 + 2x^2 - 5x - 6 that is closest to (0,0).

Could you please show your work if you understand this, and explain it please! Thanks

2006-10-23 15:13:20 · 4 answers · asked by Anonymous in Mathematics

How do the layers visible in sedimentary rock form and why do they differ?

2006-10-23 15:11:42 · 5 answers · asked by Anonymous in Earth Sciences & Geology

Peggy earns $0.68 per piece as a garment worker. What are her total weges if she had the following production rate?

Monday 81
Tuesday 88
Wednesday 92
Thursday 93
Friday 89

2006-10-23 15:10:26 · 8 answers · asked by Katherine M 1 in Mathematics

2006-10-23 15:08:31 · 5 answers · asked by Vancouver Island Marmot 1 in Zoology

explain how to do this please! i know its easy I just cant remember.

2006-10-23 15:06:59 · 14 answers · asked by jose u 1 in Mathematics

I have several questions regarding to limits:
1. what is the limit of ln x as x approaches infinity?
2. how do you find the limit of (u^2+1)^1/2,as u approaches infinity?
3. can anyone tell me how to do the limit of cos (1/z) as z
approaches 0+ using the L' Hopital rules?

I need your guys help, this is not my homework but I just want to practice some limit problems! thanks

2006-10-23 15:06:51 · 4 answers · asked by ? 1 in Mathematics

...why do some people still think the world is only 6000 years old???

2006-10-23 15:06:32 · 14 answers · asked by M 2 in Astronomy & Space

i'm working on a problem. it's a square and u have to find the value of x, the sides r x+3 and x+3

2006-10-23 15:02:50 · 4 answers · asked by Anonymous in Mathematics

We were haveing a disscussion in class today and I was wondering what you guys think of it
The debate was that what is the point of developing concepts that employ frictionless surfaces, ignore air resistance, ect. are bogus because they have no meaning in the real world; and therefore are of no use to us and instead of focusing on things like this we should be focusing on "real physics" instead

I was just wondering what everyones opinion was
thanks alot!

2006-10-23 15:02:37 · 9 answers · asked by indrul1 3 in Physics

2006-10-23 15:00:39 · 6 answers · asked by Emily<3 1 in Earth Sciences & Geology

if everything is in motion, why is there no change?

2006-10-23 14:56:51 · 12 answers · asked by M 2 in Astronomy & Space

I hear radio stations at night before i fall asleep. I can hear music, commericals, DJ's just like i have a radio on, but I don't. I've told my friends and family that I can hear all of this and they say I'm crazy and don't believe me. I've heard this for a very long time. I feel that some how the motor in the fan acts as a receiver and the virbration of the fan acts as a speaker. I turn the fan off and then I don't hear it anymore. I can pick this up on osculating {sp?} fans and also ceiling fans. Please answer my question, I'm begining to believe I'm crazy too.

2006-10-23 14:56:22 · 15 answers · asked by Anonymous in Other - Science

(5a^2w) / (2bc^3) - (3y) / (10a^2c)

is this like simplifying?
I have this:

(25a^4w-3bc^2y) / (10bc^3a^2)

Is this correct?

2006-10-23 14:55:40 · 4 answers · asked by SCHNITZEL 1 in Mathematics

Theres a tryangle one sie id 17in other 18in and the 3 one 10in. theres a circle in it as big as it can be whats its area

2006-10-23 14:52:32 · 3 answers · asked by hazzle_eyed_goddess 1 in Mathematics

Using quadratci formula find roots in somplest radical form
x^2=6x+1
2x^2-9=0
x^2=6x+31
x(x+4)=1

USing quadratics, x must = simplest radical form
x^2=6x+11
3x^2-5=0
x(x+8)=34

How would i do that pleas explain step by step

2006-10-23 14:52:29 · 3 answers · asked by Mr. X 3 in Mathematics

2006-10-23 14:48:36 · 7 answers · asked by bball3910 1 in Engineering

2006-10-23 14:48:23 · 6 answers · asked by Daysha A 1 in Astronomy & Space

2006-10-23 14:48:18 · 1 answers · asked by bowwowzbabiigurl309 2 in Physics