Science & Mathematics - 1 December 2006

A large globe, with a radius of about 5m , was built in Italy between 1982 and 1987. Imagine that such a globe has a radius R and a frictionless surface. A small block of mass m slides starts from rest at the very top of the globe and slides along the surface of the globe. The block leaves the surface of the globe when it reaches a height h above the ground.

Using Newton's 2nd law, find Vcrit, the speed of the block at the critical moment when the block leaves the surface of the globe.
1. Assume that the height at which the block leaves the surface of the globe is hcrit.
Express the speed in terms of R, hcrit, and g, the magnitude of the accleration due to gravity. Do not use in your answer theta.

2.Use the law of conservation of energy to find vcrit . This will give you a difference expression for than you found in the previous part.
Express in terms of R, h, and g.

3.Find the height from the ground at which the block leaves the surface of the globe. Expressin termsR

2006-12-01 04:30:00 · 2 answers · asked by Anonymous in Physics

2006-12-01 04:26:16 · 1 answers · asked by Nina M 1 in Mathematics

2006-12-01 04:25:25 · 1 answers · asked by *fireflies* 2 in Physics

2006-12-01 04:24:11 · 1 answers · asked by jyothi r 1 in Engineering

a pinion with the number of teeth N of 20 meshes with a gear having a number of teeth N2 of 55. The spur gear set has the diametral pitch P of 6 teeth per inch. Determine the pinion d1 pitch diameter and the gear d2 pitch diameter.

2006-12-01 04:20:29 · 1 answers · asked by DtAn 1 in Engineering

I was looking at this problem when I began thinking about the relationship:

When electromagnetic radiation of
wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a
kinetic energy of 1.68 ×105 J mol–1. What
is the minimum energy needed to remove
an electron from sodium? What is the
maximum wavelength that will cause a
photoelectron to be emitted ?

2006-12-01 04:19:35 · 4 answers · asked by ishisgreat 1 in Physics

communication between minds by some means other than sensory perception.

Also called mental telepathy


Communication through means other than the senses, as by the exercise of an occult power.


Can any one explain how and Why this happens?

2006-12-01 04:19:06 · 4 answers · asked by prem 2 in Other - Science

2006-12-01 04:17:09 · 4 answers · asked by steven i 1 in Weather

OK, we are told that polonium poisoning can only happen if we eat it or breathe it. Suppose we do receive a minute dosage. Does this mean that if we have no symptoms and no problem for a reasonable amount of time we are fine, or can it cause long term problems to health, like cancer, etc? What about pregnant women? I mean OK, it is obviously unlikely that we have all been poisoned on the BA planes and that we will die like Litvinenko, but what about minor-minor exposure, can't that do any harm in the long run? Is it you are either poisoned or you are not and have escaped it, or can it affect you secretely, with no symprtoms?

2006-12-01 04:12:06 · 4 answers · asked by cpinatsi 7 in Chemistry

Is there a site that gives quick keyboard commands for commonly used math symbols? Like alt + 246 creates the "÷" sign. I need more.

Thanks!

2006-12-01 04:11:31 · 2 answers · asked by Chris R 1 in Mathematics

2006-12-01 04:09:31 · 4 answers · asked by asianchoc 1 in Chemistry

2006-12-01 04:09:23 · 3 answers · asked by fantfoot25 1 in Mathematics

2006-12-01 04:08:58 · 5 answers · asked by fantfoot25 1 in Mathematics

a. epidermal cell walls
b. stomata
c. walls of the guard cells
d. xylem

2006-12-01 04:08:30 · 0 answers · asked by 9929 3 in Botany

2006-12-01 04:08:22 · 2 answers · asked by fantfoot25 1 in Mathematics

If so how much did you get and where are you located??

2006-12-01 04:07:49 · 22 answers · asked by Anonymous in Weather

a. veins and arteries
b. palisade parenchyma and spongy parenchyma
c. upper and lower epidermis
d. none of the above

2006-12-01 04:07:27 · 1 answers · asked by 9929 3 in Botany

i love to watch them every year but have no idea which they are can somebody with good knowledge of this please help me, or point me in the right direction of help, thankyou so much.

2006-12-01 04:06:14 · 2 answers · asked by adams girl 2 in Zoology

a. lipids
b. carbohydrates
c. nucleic acids
d. proteins

2006-12-01 04:06:13 · 1 answers · asked by 9929 3 in Botany

2006-12-01 04:04:04 · 4 answers · asked by steeno_86 1 in Mathematics

A girl pushes a box 300N at 2 m/s. She stops pushing the box and it comes to rest 3 seconds later. How large is the force of friction on the box?

A. 20 N
B. 50 N
C. 150 N
D. 200 N
E. 300 N

2006-12-01 04:03:26 · 4 answers · asked by James R 1 in Physics

8.What is the name given to a statement that has been proven by deductive reasoning?

A.
conjecture

B.
postulate

C.
property

D.
theorem

2006-12-01 04:00:57 · 16 answers · asked by Anonymous in Mathematics

2006-12-01 04:00:39 · 16 answers · asked by Anonymous in Astronomy & Space

a. cell membranes
b. DNA (nucleic acids)
c. ATP
d. proteins

2006-12-01 03:59:29 · 2 answers · asked by 9929 3 in Biology

2006-12-01 03:59:05 · 9 answers · asked by grey_chocobo 1 in Astronomy & Space

I have heard recent news about CERN creating a black hole on earth to explain how the universe began. As in accordance with what we knmow about black holes does creation of a black hole on earth pose potential threat to mankind?

2006-12-01 03:58:40 · 11 answers · asked by lightinblaze 2 in Astronomy & Space

If ( 1+x )^y = a0 + a1x + a2x^2 + a3x^3 + ... + ayx^y, where y is a positive even number, show that
a0 + a2 + a4 + a6 + ... + ay =( 2^y / 2).

2006-12-01 03:58:38 · 2 answers · asked by Anonymous in Mathematics

I know that it is the scientific name of one of the classes of Annelids, i was just wondering, where it originated from.

2006-12-01 03:58:12 · 5 answers · asked by needtoknow 1 in Biology

I believe that our planet in this galaxy is the "past" of the same planet from another galaxy. This would explain deja vu. When someone experiences deja vu, they get the sense that they have already experienced a certain situation, which they have, but in a different galaxy.

Basically, it's like there are two exact replicas of everything- one in this galaxy (the past) and one in another galaxy (the present). This planet is reliving events down to the last detail that have already happened in another galaxy- every moment, word, movement, and breath.

2006-12-01 03:57:22 · 6 answers · asked by Anonymous in Astronomy & Space

how do you determine polarity, and what is the answer to this?

Which of the following molecules is most polar?

a. Cl2
b. HCl
c. NO
d. IBr
e. H2

2006-12-01 03:55:13 · 3 answers · asked by Anonymous in Chemistry