Science & Mathematics - 21 November 2006

Why do leaves change their colour in autumn?
Why some stay green?
Why trees lose leaves in autumn/winter?
and the trees are still alive evem all leaves were gone?

2006-11-21 21:05:23 · 7 answers · asked by Judy 1 in Botany

1. Prove that any straight line drawn to form the vertex of a triangle to the base is bisected by the straight line that joins the midpoints of the other sides.

2. AD and BE are the altitudes of an isoscles triangle ABC with AB = BC. Prove that AE = BD

3. In a triangle ABC, the bisector of angle A meets base BC at D. Prove that AB>BD

4. In a triangle PQR, S is any point on QR. Prove that PQ + QR + PR > 2PS

5. If two isosceles triangles have a common base, then prove that the line joining their vertices bisects them at right angles.

6. In triangle ABC, D is the midpoint of AB and P is any point on BC. A line CQ is drawn parallel to PD to meet AB at Q.
Prove that ar(BPQ) = 1/2 ar(ABC)

2006-11-21 20:57:52 · 6 answers · asked by Akilesh - Internet Undertaker 7 in Mathematics

2006-11-21 20:54:51 · 2 answers · asked by JustJane 6 in Botany

2006-11-21 20:52:49 · 4 answers · asked by Anonymous in Geography

what're the important characterisitcs that is detrimental to the cement quality? is there a makeshift procedure/method that can be used instead to test for such characteristics?

2006-11-21 20:51:20 · 2 answers · asked by crimsiris 2 in Engineering

have they been working on nuclear fusion energy project?
If so what is the staus of that project?
It is my understanding that a consortium in France will be building the world's first large scale fusion reactor.

2006-11-21 20:43:31 · 2 answers · asked by heknew1 1 in Engineering

for example how much lumens value in a 14 lux light?

2006-11-21 20:41:45 · 4 answers · asked by wakiz50 1 in Physics

2006-11-21 20:36:52 · 10 answers · asked by Friend 1 in Physics

2006-11-21 20:34:37 · 5 answers · asked by kaye s 2 in Chemistry

We did a lab where we burned magnesium (to create magnesium oxide), then added water and heated again in a crucible with the cover ajar to release any Magnesium Nitride created.

The question on the lab report is this: if water had not been added to your initial product, a mixture of MgO and Magnesium Nitride (Mg3N2?) what error in the percentage magnesium determined would have resulted?

I will greatly appreciate any help on this! :)

2006-11-21 20:28:27 · 1 answers · asked by tiggywinkle 3 in Chemistry

2006-11-21 20:24:06 · 15 answers · asked by Mike H 2 in Mathematics

This question is about monkies:

If he (male) is called a monkey then what do you call a she (female) monkey in english ?

2006-11-21 20:13:49 · 12 answers · asked by avissoft 1 in Zoology

Im an amature herpetology enthusiast and Im curious to know if thermal gadgets could assist me in the field at night.

2006-11-21 20:11:58 · 8 answers · asked by xmullensk8r 1 in Zoology

2006-11-21 19:54:13 · 1 answers · asked by ih8p6 1 in Botany

2006-11-21 19:52:12 · 6 answers · asked by kooshal 2 in Physics

2006-11-21 19:51:55 · 10 answers · asked by Anonymous in Earth Sciences & Geology

2006-11-21 19:44:20 · 7 answers · asked by cute gal 1 in Physics

2006-11-21 19:43:28 · 4 answers · asked by Anonymous in Earth Sciences & Geology

2006-11-21 19:39:32 · 5 answers · asked by Anonymous in Other - Science

Once I was in a bathroom and to my surprise I saw electrical current traveled from the wall plug to the castiron bath.
Never mind about the safety in it, my interest is concerned more on the possibility of a new invention: Sort like radio frequency.
Or should I go to the bathroom more often!

2006-11-21 19:37:45 · 13 answers · asked by Anonymous in Engineering

Could you help find any online articles or any site that contains info about the relationship of metabolism to the growth of an organism? if its for bivalves, it will be really great. but any organism will do.! thank you!

2006-11-21 19:35:05 · 1 answers · asked by Sofia 1 in Other - Science

2006-11-21 19:33:30 · 5 answers · asked by Anonymous in Chemistry

The question is related to +2 level maths. Let me know some maths related sites.

2006-11-21 19:31:51 · 6 answers · asked by shank622 1 in Mathematics

2006-11-21 19:19:53 · 17 answers · asked by JeSui 2 in Geography

how to get fullwave rectified output 1.4v above x-axis.u r given sine wave input.this has to be done without using any dc source

2006-11-21 19:16:58 · 4 answers · asked by firebolt 2 in Engineering

wha is about the lithosphere?what are the parts of it?

2006-11-21 19:15:43 · 6 answers · asked by abigail a 1 in Geography

2006-11-21 19:14:55 · 4 answers · asked by astura 1 in Mathematics

Can someone please help me with naming alcohols that have more than one hydroxyl group? what is it called when there are two hydroxyl groups?

I have a diagram with what could be cyclohexanol but there are two hydroxyl groups, what is this called?

I need it for my chemistry exam tomorrow

2006-11-21 19:14:40 · 3 answers · asked by dundledee 2 in Chemistry

A friend & I were discussing the above question. We decided it must be NEITHER, or BOTH! What do others think? An example to prove our theory was that when one is sitting on a fence (eg; 00:00 is the fence) then one is either partly on both sides (eg: both days), or is EXACTLY on the fence, with NO parts of the body (eg: exact milli-second,or less) over either side.

2006-11-21 19:13:07 · 9 answers · asked by yeh_but2002 1 in Mathematics

zoology is for people who are trying to start a zoo right???

2006-11-21 19:11:21 · 7 answers · asked by [milk·bone] 2 in Zoology