Science & Mathematics - 21 October 2007

2007-10-21 23:55:48 · 7 answers · asked by choc 1 in Astronomy & Space

How much heat is necessary to change 295 g of ice at -10°C to water at 20°C?
kcal

2007-10-21 23:17:19 · 2 answers · asked by Anonymous in Chemistry

2007-10-21 22:50:57 · 3 answers · asked by ehgirl 2 in Biology

Please show some working, I need to know how to do it.

Thanks.

2007-10-21 22:40:48 · 11 answers · asked by Hermione Granger 4 in Mathematics

Could the universe really be splitting everytime we do something? Is it really impossible? Should they teach this is university classes, or even high school classes? Or should Niels Bohr theory still be taught?

2007-10-21 22:38:35 · 4 answers · asked by Anonymous in Physics

This is to determine which is more important for each and every living human being here on Earth, Science or Religion.

2007-10-21 22:31:45 · 14 answers · asked by Ramy 1 in Other - Science

2007-10-21 22:26:07 · 21 answers · asked by Anonymous in Paranormal Phenomena

You find an unlabelled bottle on the bench. When you test the liquid in the bottle with Universal Indicator, you find that the liquid has a high pH number of 4. Which of the following statements is true?

a) The liquid is salt solution
b)The liquid is an acid
c)The liquid is an alkali
d)The liquid is a weak acid
e)The liquid is a sodium hydroxide solution
f)The liquid is hazardous

2007-10-21 22:18:27 · 10 answers · asked by b b 1 in Chemistry

2007-10-21 22:12:53 · 1 answers · asked by Anonymous in Earth Sciences & Geology

2 parallel window panes ( Area=0.5m^2 and o.oo6m thick) Are seperated by 0.006m of air.The inside of the glass is 24C and the outside is 3C. How much heat will be lost by conduction per hour?

2007-10-21 22:06:09 · 1 answers · asked by RockNRollStar 1 in Physics

At a given moment, a plane passes directly above a radar station at an altitude of 6 miles. The plane's speed is 500mph. (after drawing a diagram) Suppose that the line through the radar station and the plane makes an angle θ with the horizontal. How fast is θ changing 10 min after the plane passes over the radar station?

2007-10-21 21:46:02 · 2 answers · asked by Anny P 1 in Mathematics

A passenger is pulling on the strap of a 15.0kg suitcase with a force of 70.0N. The strap makes an angle of 35 degrees above the horizontal. A 37.8N friction force opposes the horizontal motion of the suitcase. Determine the acceleration of the suitcase.

I'm okay with most force questions, but I have no idea what to do with the angle.

2007-10-21 21:43:34 · 6 answers · asked by bezi_cat 6 in Physics

I know Pluto has been declasified to a dwarf planet.
But in schools I see they are still teaching nine plants in the solar system plus planet "X".

Whats the story, the name of plant "X" and what should we be teaching in our schools on ths subject.?

Thank you for your input

2007-10-21 21:26:54 · 13 answers · asked by Anonymous in Astronomy & Space

Prove that 4|(x-y) is relation of equivalency.

This is gonna be on my exam in 3 hours T_T how do I answer it?

2007-10-21 21:26:33 · 1 answers · asked by Anonymous in Mathematics

it is stiff as a board!, if i stretch it`s wings would it glide?

2007-10-21 21:25:56 · 13 answers · asked by SARNIE 3 in Zoology

Prove that the copying f:R->[1,+∞), f(x)=x²+1 is surjection but not injection.

How T_T, I got exam in 3 hours lol

2007-10-21 21:24:28 · 2 answers · asked by Anonymous in Mathematics

A plane is moving due north, directly towards it destination. Its airspeed is 200 mph. A constant breeze is blowing from west to east at 20 mph. In which direction is the plane pointed.

The answer to this question is 5.7 degree W of N...but i dont know how to get that answer...can someone please explain...

2007-10-21 21:22:14 · 3 answers · asked by smilenhope 1 in Physics

2007-10-21 21:21:08 · 5 answers · asked by lil1 2 in Astronomy & Space

What is the equation of a tangent line if y=(x^2-1)/(x^2+1) and (0,-1)?

I found y' first which i got 4x/(x^2+1)^2
But, when i put 0 into the function, i got the slope of 0.
So, the final equation became y+1=0.
And, it does not seem to me the answer...


Can you plz check and tell me how to reach the right answer?

Thanks :)

2007-10-21 21:13:32 · 3 answers · asked by heyheyhey 2 in Mathematics

2007-10-21 20:59:17 · 22 answers · asked by Anonymous in Zoology

(Use the identities to find the values of the six trig functions.)
Can someone please explain the process of figuring these kinds of problems out?

1.) x, given cos2x=(-5/12) and pi/2 < x < pi
2.) 2cos^2(67 1/2)-1

2007-10-21 20:58:15 · 1 answers · asked by Anonymous in Mathematics

2007-10-21 20:54:16 · 10 answers · asked by usman z 1 in Physics

2007-10-21 20:48:30 · 7 answers · asked by boacmarinduque 1 in Zoology

So I'm still having a bit of trouble understanding the concept of this 'derivative with time' statement.

Take for instance this problem:
circle with radius r. If dr/dt = 4
find dA/dt when r = 3

So...you take pi(r)^2 and take its derivative.
Ok. So the hardest problem with me is understanding what I need to do first. What is it I AM LOOKING for...

or another instance is...
xy = 5
let dy/dt = 1
find dx/dt when x = 1

its all so cumbersome to me still.

2007-10-21 20:48:10 · 3 answers · asked by ret80soft 1 in Mathematics

2007-10-21 20:45:08 · 8 answers · asked by nk 1 in Mathematics

2007-10-21 20:44:40 · 3 answers · asked by aryan e 1 in Physics

please help me with this question

determine a particular solution of my'' + cy' + ky = Fcos(wt) of the form Acos(wt - homogeneous solution)

show that the amplitude A is a maximum when w^2 = k/m - 0.5(c/m)^2

thanks so much

2007-10-21 20:43:24 · 1 answers · asked by phil h 2 in Mathematics

i was just wondering if only MOTHER EARTH was as big as say jupiter!!!
which country occupied how much area???

2007-10-21 20:37:18 · 8 answers · asked by Anonymous in Astronomy & Space

2007-10-21 20:33:58 · 5 answers · asked by aryan e 1 in Astronomy & Space

A guy wire which is 14m long is fastened from the ground to a pole 6.7m above the ground. Find the angle the wire makes with the ground.

2007-10-21 20:33:39 · 3 answers · asked by angilyn c 1 in Mathematics