Physics - September 2007

If mass of earth is 5.98e24 kg and its diameter is 15000 km.
How can I get constant (a)?

2007-09-07 06:48:49 · 3 answers · asked by Blacksmith 2

Don't they know mercury could be poisonous. Dyed alcohol would be much safer, right?

2007-09-07 06:44:41 · 5 answers · asked by Alexander 6

2007-09-07 06:41:06 · 8 answers · asked by Alexander 6

What is the probablity of two people on different sides of the planet coming up with the exact same idea with no contact between each other

2007-09-07 05:39:46 · 16 answers · asked by Outtamyway 1

Son's homework. He needs 8 properties of an ideal fuel. I don't even understand the question!

2007-09-07 05:15:59 · 5 answers · asked by Anonymous

What is the difference for user in terms of coverage/reception in different frequency bands? i.e. does GSM 1800 have better coverage than GSM 900? Why does a lower frequency band show better penetration power? We studied that a baseband signal is modulated to have "higher" frequency to gain distance. Aren't these statements contradictory? Does GSM 1800 cover less area but with better voice quality? Please help!

2007-09-07 04:34:06 · 2 answers · asked by Stallion 1

when rain falls from the sky, what becomes of its momentum as it hits the ground?
is your answer also valid for newton's famous apple? Explain
=============================
the first one i know...but the second one..what the hell is it talking about??

this is a question from my textbook.

2007-09-07 04:22:26 · 5 answers · asked by Anonymous

i would really want to know are there any proofs to prove that we can travel to the past or the future?

2007-09-07 04:17:40 · 5 answers · asked by S2marbles 2

2007-09-07 04:15:30 · 6 answers · asked by Anonymous

Note that a sequence of links from a higher level theory to particle physics (e.g. evolution to biochemistry, etc) in itself is a weak evidence for a reduction because of the modeling and assumptions used. Some say that reductions are too complex to prove, these links are the best we can do, so the evidence is strong. It's a strange logic. These links are strong evidence for some relationship between the theory and a more elementary one, for some kind of reduction, but not necessarily for the (standard) reduction. So, we have evidence for the successful application of elementary particle physics in chemistry, etc, but unless one carefully consider the models and the assumptions used, we don't know if these links correspond to the standard reduction.

Do you know if someone made such a study? For example, someone might have attempted to find some recurring pattern in the assumptions and models used to see if there is an indication of a special kind of reduction.

2007-09-07 04:05:25 · 3 answers · asked by My account has been compromised 2

This question is about equilibrium on physics. Please help me. Thank you.

2007-09-07 03:52:51 · 10 answers · asked by bridjE 1

How long did the Hundred Years War last?

2007-09-07 03:40:38 · 4 answers · asked by B 1

2007-09-07 02:50:02 · 5 answers · asked by dodi142004 1

Does anyone else think its funny/ridiculous during the air hostess demonstrations that they say in case the plane lands on water the seat can be used as a float. Who has ever heard of a commercial jet land successfully on water. Please someone explain if its possible to do this and why the gov allows airlines to give this false sense of security.

2007-09-07 02:40:37 · 10 answers · asked by ? 1

Calculate the net torque about the axle of the wheel shown in the link below. Assume that a fraction torque of .30 Nm opposes the motion.

http://img293.imageshack.us/my.php?image=circle2me6.jpg

2007-09-07 02:36:45 · 3 answers · asked by physics maniac 2

2007-09-07 02:30:52 · 5 answers · asked by Anonymous

When an evaporated sweat rate of 0.26 litres (kg) per hour corresponds to a heat loss of 100 Wm-2. to maintain heat balance the body would therefore have to produce 0.454 litres of sweat per hour that is

R = 1 - 0.932
2
Sreq = 97.88
0.56

= 174.79 wm-2
= 0.454 litres per hour.

How did they work out it was 0.454 litres per hour?

2007-09-07 02:27:28 · 3 answers · asked by Missy S 2

The semimajor axis of Jupiter around the sun is 1.8x10^8km. An asteroid in the asteroid belt has an orbital period half that of Jupiter. What is the semimajor axis of the asteroid's orbit around the sun ?

2007-09-07 02:23:42 · 1 answers · asked by David M 1

I'd like an example of this please.

2007-09-07 02:20:27 · 10 answers · asked by Anonymous

2007-09-07 00:41:56 · 6 answers · asked by Gershom N 1

A radio controlled toy car increases speed over a distance of 15.2 m. If the car starts at rest and has a final speed of 0.76m/s, what is the magnitude of it's acceleration?

A barge moving with a speed of 1.00m/s increases speed uniformly, so that in 30.0s it has traveled 60.2m. What is the magnitude of the barge's acceleration?

2007-09-07 00:28:58 · 5 answers · asked by Anonymous

a)Compare the work done by the boy in running and walking upstairs.Why?b)Compare the power the boy expended in running and in walking.Why?c)Which will be tiresome running or walking upstairs?Why?

2007-09-06 23:05:12 · 3 answers · asked by Anonymous

Suppose we observe a Lever in equilibrium, why is the FORCE exerted by the fulcrum on the board NOT considered as part of the system if we talk about TORQUE?

2007-09-06 22:11:04 · 2 answers · asked by Anonymous

Traditionally, quantum calculations were structured in terms of statistical probability, ie. the notion of subatomic processes being indeterministic. Some people such as Einstein and Hooft have proposed or believed in the idea of "hidden variables", ie. the idea that if we believe quantum processes are indeterministic, we must have forgotten to take something into account. They believe that a future theory, or observations, will one day demonstrate determinism.

My questions are
A) What is the latest scientific consensus on this?
B) If most scientists believe in quantum indeterminism (or aren't sure), how are philosophers such as Daniel Dennett (for example, in "Freedom Evolves") arguing against free will? What rational cases are being made for saying that free will is an illusion?

I'm guessing a case can be made, but if quantum indeterminism is still generally accepted, I don't see how such cases could be rooted in empirical evidence.

Please cite sources if possible. Thanks.

2007-09-06 21:14:53 · 3 answers · asked by Anonymous

Is meditative travelling in time and space the same as travelling through worm holes where time-space fabric is distorted to an extent that two distant points meet each other and once can simply step into another time-space ?? Is it that yogis/meditators use mental powers to distort time-space fabric and thus travel back and forth in no time ??

2007-09-06 21:10:33 · 3 answers · asked by anil c 2

A guy rides south on his bicycle in a straight line for 15. min. with an average speed of 12.5 km/h, how far has he ridden?

Distance=12.5 km/h/15 min.

12.5 km/h / .4 hrs.
Distance equals 3.125 kilometers right?

2007-09-06 20:44:49 · 7 answers · asked by Anonymous

Suppose the first rock in Conceptual Checkpoint 2-5 drops through a height h before the second rock is released from rest. Show that the separation between the rocks, S, is given by the following expression:
S=h+(square root of (2gh))t
In this result, the time t is measured from the time the second rock is dropped.

2007-09-06 20:31:56 · 2 answers · asked by Anonymous

You shoot an arrow into the air. Two seconds later (2.00 s) the arrow has gone straight upward to a height of 30.0 m above its launch point. (a) What was the arrow's initial speed? (b) How long did it take for the arrow to first reach a heightof 15.0 above its launch point?

2007-09-06 20:18:50 · 1 answers · asked by Anonymous

The vacuum compartment inside of a thermos would probably have atotal exposed area of about 1square ft. The amount of atmosphereic pressure on 1sq ft would be about 1000lbs! But when i looked inside of my thermous it apears to be just a relatively thin set of glass jars.

Why doesn't the atmosphere shatter it?

ALso, i saw on mythbusters that they have a big vaccum chamber and the clear door on it is about four inches thick! Why the difference?

2007-09-06 20:10:05 · 4 answers · asked by gentlest_theirsintheworld 2

I've heard we live in 3 dimensions but there are more possibly up to 10 different dimensions and I would like to know exactly what that means.
Does it mean three sides to everything or 10 sides to everything?
What does it mean?!!!!!

2007-09-06 20:03:48 · 6 answers · asked by Adelaide B 5