Science & Mathematics - 2 December 2007

Why are some materials (iron, steel, heamatite) magnetic and others (like copper or aluminium) not? If it's about electron spin and alignment, why aren't all electrical conductors also magnetic or attracted to magnets even if they're not actually magnetic themselves, afterall they generate EM fields when a current is induced in them? Are there any magnetic or magnetisable non-metals? Why are only ferrous (iron based?) metals affected?

2007-12-02 21:59:57 · 1 answers · asked by Doom 2 in Physics

1 An astrounaught on the Moon threw an object 4m vertically upwards and caught it again 4.5 seconds later. Calculate:
a) the acceleration due to gravith of the Moon,
b) the spped of projection of the object,
c) how high the object would have risen on the Earth, for the same speed of projection

2 A swimmer swims 100m from 1 end of a swimming pool to the other end at a constant speed of 1.2m/s, them swims back at constant speed, returning to the starting point 210 s after starting.
Calculate how long the swimmer takes to swim from: (i) the starting end to the other end, (ii) back to the start from the other end.

Please show working out and which equation of motion used!

2007-12-02 21:57:58 · 3 answers · asked by Selly 3 in Physics

what is the relation betwen the glucose concentration and the the wave legth of the detected light by the PD after IR spectroscopy if we use the infrared spectroscopy to deteced the glucose of the blood

2007-12-02 21:55:34 · 1 answers · asked by alisa w 1 in Engineering

Can any of you define the difference between a spectacle blind and a spade blind and are there any good website links where I can get more information?
Thanx

2007-12-02 21:43:34 · 3 answers · asked by ipoian 5 in Engineering

integral of sqrt(1-x^2)dx
integral of sqrt(x^2-1)dx
integral of sqrt(x^2+1)dx

no formulas...need to prove them :( PLease help its 3:45 am and I've been up all night!

2007-12-02 21:43:06 · 2 answers · asked by cutiemutie9 1 in Mathematics

2007-12-02 21:39:57 · 4 answers · asked by Anonymous in Geography

2007-12-02 21:16:25 · 2 answers · asked by Answer Seeker 1 in Mathematics

Given that velocity = v(t) = tlnt - t , find the expression (or anti-derivative) for the position x(t).

I don't know how to take the anti-derivative of the tlnt part =\

2007-12-02 21:07:26 · 3 answers · asked by Jessicaaaaa 1 in Mathematics

i need this answered for my science work ASAP

2007-12-02 20:58:50 · 11 answers · asked by Anonymous in Astronomy & Space

Why is it that when you look at the ocean, it appears to the color of Blue. But when you get some water from the ocean,it appears to be transparent. Why is this so?

2007-12-02 20:57:05 · 6 answers · asked by Anonymous in Earth Sciences & Geology

Do you know any animals with a unique characteristic.
I have to expain, then draw it.
:P
Any ideas?

2007-12-02 20:54:24 · 11 answers · asked by cm 1 in Zoology

how can i find the dimensions of the lower base of a frustum of a rectangular pyramid if only the volume,height & the dimensions of the upper base are given?

2007-12-02 20:46:32 · 2 answers · asked by mhymhymhymhymhymhymhy 2 in Mathematics

Hi
I have the follow problem:
An essay written in the English language is 3000 words long. Assuming that the English alphbet consists of 26 upper case letters, 10 numerals and 20 punctuation marks, and the average word length si 6 characters, (a) Calculate how long it will take to transmit the whole essay through a channel band limited to 2kHz (b) How can the time calculated in (a) be reduced, without losing any information.

Can anyone please explain this to me? thnx :)

2007-12-02 20:43:36 · 1 answers · asked by Danielle 3 in Engineering

When Xn = (n^(-2))*(log(n))^4
How do you work it out?
Thanks.

2007-12-02 20:41:57 · 1 answers · asked by Dave_G 2 in Mathematics

What was the coolest Star Trek ship?

2007-12-02 20:31:19 · 11 answers · asked by christiantrekkie 4 in Astronomy & Space

i want to make a volcano model & in our school there is a science exhibition & we means our team chosen that we would be able to make a volcano model & people will enjoy to see it.

2007-12-02 20:28:26 · 1 answers · asked by Anonymous in Earth Sciences & Geology

A rower travels upstream at 6km per hour and back to the starting place at 10km per hour. The total journey takes 48 minutes. How far upstream did the rower go?

2007-12-02 20:24:49 · 7 answers · asked by Anonymous in Mathematics

2007-12-02 20:22:29 · 2 answers · asked by Anonymous in Earth Sciences & Geology

Im a 15 year old so give me some slack and yeah I never witnessed the moon landings ofcourse however I have seen repeats from youtube and I have considered that maybe the reason NASA might of faked a moon landing was because of their fear of the Soviet Union because if you research the past they werent far in front of the Soviets and the only evidence of them beating the Soviets were through the apollo missions. Also why would they just hault after going to the moon and a few times afterwards ofcourse they do nothing for 30 years and then anounce now they want to go back in 2020? Seems strange to me that they would go back with men when they could just use robotics by then anyway at the rate there advancing I mean look at ASIMO he could lead the mission (kidding!). If you say its cause it costs a lot of money to go to the moon well thats not a matter when americas in debt and has been before the missions.

Please dont lecture me but I would like answers to why man needs to go back?

2007-12-02 20:18:51 · 17 answers · asked by man_united99 1 in Astronomy & Space

my cousin has a very big problem... she has a very large jaw,, what are the solutions for it... is there a surgery???

2007-12-02 20:16:49 · 4 answers · asked by claire 2 in Medicine

parabola y=4-(x)^2 cuts x axis at R and S... P (x,y) lies on parabola in 1st quadrant, and Q lies on parabols such that PQ is paralel to the x-axis...

i already worked out R is (-2,0) and S is (2,0)

now i need to show area of trapeziumb PQRS is given by:
A = (2-x)(4-x^2)
aaargh!!??? wat!? Area of trapezium = 1/2(a + b)h... but not much help?

then i need to find value of x which gives the maximum value of A... but i think i can work that out if i get this.

pls help, thanx heaps :)

2007-12-02 20:10:29 · 3 answers · asked by Anonymous in Mathematics

(explain the distributive property)

Area: (2x +1) ( x+3) = 2x + 7x + 3
which is: length: 2 + 1 width: + 3

What's the pattern that would work with all of them?other random ones?

(PS: this is grade 8 stuff...)

2007-12-02 20:03:55 · 1 answers · asked by Zobbiezob 3 in Mathematics

solve by completing the square
can anyone help me solve this?
thanks

2007-12-02 20:01:06 · 5 answers · asked by ca481 1 in Mathematics

Every time they show a skull of a 'hominid' or transitional form of man, I see...a monkey skull. They are distinctly different.

The Fossil record destroys Evolution, but the evolutionary faithful keep on touting each find as proof of evolution. But proof to whom, those who wish to believe, or those who still question everything and are actually scientific.

If you have no transitional forms between Ape & Man, then how do you come to conclusion that Chromosome #2 in Man is a fussion of Ape Chromosomes taking us from 48 to 46?

The answer - assumption. You cannot prove it, you can only and I quote, "think it may have happened".

2007-12-02 19:41:16 · 22 answers · asked by Tim L 2 in Biology

i am just really stuck.

Find the standard form of the number
1. 9(cos0 + isin0) (note:its zero not theta)

Perform operation and leave in trigonometric form.
1. [(3/2)(cos pi/6 + isin pi/6)][6(cos pi/4 + i sin pi/4]

2. 9(cos20 + isin20)/5*(cos75 + isin75)

2007-12-02 19:39:35 · 2 answers · asked by Anonymous in Mathematics

2007-12-02 19:36:07 · 6 answers · asked by Anonymous in Zoology

I am having a discussion with a friend in australia and would like to know if it is the polar bear or not that is the deadliest animal in Canada.

2007-12-02 19:33:57 · 7 answers · asked by Kelli F 1 in Zoology

A 3900 kg truck traveling with a velocity of 11.5 m/s due north collides head-on with a 1450 kg car traveling with a velocity of 24 m/s due south. The two vehicles stick together after the collision.

What are the size and direction of the total momentum of the two vehicles after they collide?

2007-12-02 19:29:20 · 2 answers · asked by jay 1 in Physics

Ok ok, I know, it's 3:30 am, but this is an emergency!! As funny as it may seem, I need to know this ASAP. Isn't there some thing that on one or two days of the year, the sun will shine straight down 7th Avenue, or some other avenue or street, in New York City? I don't know exactly what, but I really need to know! And fast, too!
Thank you.

2007-12-02 19:27:35 · 3 answers · asked by Joshua Z 4 in Weather

This question is for all you people interested in time travel, and anybody else is welcomed to answer this question to. I always wondered which would be more fun, to go back or forward in time. If you go way forward in the future, then chances are you could be flying cars in the air like planes, which would be so awesome. If you go way back in time, then you can see what dinosaurs really looked like and well that would be quite the adventure. I'd probably pick the past because of that, what do you think people?

2007-12-02 19:16:24 · 13 answers · asked by Zick1234 2 in Astronomy & Space