Physics - December 2007

2007-12-15 00:36:07 · 6 answers · asked by JAMES H 2

I have to write an essay about speed of light and i have to prove either that the speed of light actually isnt constant, or that it is constant and time travel is possible. But i dont really get what time travel has anything to do with it. also i really dont get speed of light in general. why is it constant?

2007-12-14 23:48:35 · 10 answers · asked by jbdrummergirl93 2

An accident at a UK nuclear reprocessing plant caused an area of local moor-land to be contaminated with the radioactive isotope cobalt-60, which has a half-life of 5.23 years. The radioactivity of the moor-land just after the accident was measured at 500 bequerels.m-2.

Public access to the moor-land was restricted until the level of radioactivity
fell to 1.0 bequerel.m-2. How long must access be restricted ?

useful equation:

In {original activity / existing activity} = k x time taken.



Hint : First use the value of the half-life and the logarithmic relationship between radioactivity and time, given above, to determine k, the rate constant.

Now use the value of k obtained to predict the access restriction time.

2007-12-14 20:50:50 · 3 answers · asked by Anonymous

2007-12-14 19:34:52 · 9 answers · asked by ryan 6

2007-12-14 19:34:42 · 6 answers · asked by Jani 1

2007-12-14 19:19:27 · 11 answers · asked by Anonymous

1. is it possible to pass light or can you only travel at the same speed as light

2. does time slow when you travel at the speed of light

3. what is the speed of light

4.do black holes suck in light and if so you cannot see them then

5.does light pass between dimentions

6. any thing else you know about this kind of stuff

2007-12-14 19:07:25 · 3 answers · asked by Anonymous

I would like to forward my idea of a black hole and time travel to you in the hope of getting your feedback.

I believe that a black hole is created by a drop of water or water particle in the outer earth’s space.

The water particle is floating along and is struck by a dust particle or something like it and the drop of water or particle implodes.

As the oxygen created from the water goes out faster then something goes in thus creating a black hole which will expand until it fills up with a heavier substance than the hole itself, and consequently closing it.

If my theory is correct, it would make it possible to create a black hole on earth.

This would open up many doors. For example it would be possible to create time travel, well not to travel back in time but to let time past you. ?

2007-12-14 18:28:30 · 5 answers · asked by Anonymous

I am looking at moving into a new home. However it has overhead electricity pylons with electricity flowing through it about 50 metres close to the house. The developer states they have done research and its safe. However i am worried about long term risk of cancer.
Please advise

2007-12-14 17:49:21 · 2 answers · asked by hdastoor 1

Some scientists have postulated that the life in the Universe is possible because we live in the Goldilocks zone or the a narrow band of right conditions. For instance, if a single one of the zones were altered, stars would never form, the universe may fly apart, DNA would not exist and so on. What do you think, it is evidence for design, or is it just a asymmetry?

2007-12-14 16:32:36 · 6 answers · asked by Anonymous

2007-12-14 16:21:35 · 3 answers · asked by Anonymous

do you think the out come would of been different?

2007-12-14 16:01:36 · 8 answers · asked by saveitok 6

Such as, say, telekinesis or something of the sort?

Obviously I don't believe anything ridiculous like someone can teleport, but theoretically if someone was to gain the control of the positive and negative ions inside of them, may be they could focus it to push a very light-weighted object.

If this is sounding familiar, I wouldn't be surprised because I got the idea from the TV series "Kyle XY". It is about a boy who (spoiler warning) was created in a gestation chamber allowing him and his brain to develop for a much longer time than 9 months (16 years) obtaining a brain superior to every human to ever live.

http://en.wikipedia.org/wiki/Kyle_XY_%28character%29#Origin

Back on topic, would any of this be possible?

2007-12-14 15:20:35 · 7 answers · asked by Channel E-D 2

A youngster shoots a bottle cap up a 21.5° inclined board at 1.82 m/s. The cap slides in a straight line, slowing to 0.92 m/s after traveling some distance. If the coefficient of kinetic friction is 0.40, find that distance.

2007-12-14 12:20:12 · 1 answers · asked by Anonymous

Ok, so i have a toothpick bridge due on the 18th of December, and I have only done the pillars. We can only use elmers glue, and have a limit of 500 toothpicks. Do you have any tips, or designs that i could use to help me out?

2007-12-14 11:51:11 · 4 answers · asked by Margo S 2

Hey i was wondering if there was an easy way to shock someone? if you know tell me! thanks guys!

2007-12-14 11:06:06 · 4 answers · asked by Rhys D 2

4 blocks m1=25kg, m2=45kg, m3=35kg, m4=25kg sit on frictionless horizontal surface connected block to block by massless string. F1 exerted to left is 67N and F2 exerted to right is 50N. Tension x (Tx) b/w m1 and m2. Ty b/w m2 and m3. Tz b/w m3 and m4. What is Ty?

<---F1____M1__Tx___M2___Ty___M3___Tz___F2--->

2007-12-14 10:31:49 · 1 answers · asked by Jenn 1

A block w/ height H, area A, and density half that of water floats (in H2O). You depress the block so that an extra length y is submerged past the equilibrium. When you release the block, what is the net force acting on it?

2007-12-14 10:07:39 · 1 answers · asked by Diane S 2

I have the Math credits that are required. I am taking Chemistry, I have completed 2 out of the 4 I need. My question is, would it be better to take all of my Chemistry classes and then take Physics 1 and 2? Would Physics be easier if I have an understanding of Chemistry or does it matter? thanks

2007-12-14 10:06:34 · 2 answers · asked by Boo Radley 4

A projectile can be fired at many angles between zero degrees (horizontally) and ninety degrees (vertically). Which angle would give the greatest horizontal displacement down range? Which pairs of angles give the same landing spot?

Please show/explain all work. Please show what formulas were used.

2007-12-14 09:40:08 · 3 answers · asked by Kantilal P 1

Taking an element such as rubidium, when it is supercooled the atoms join together to form a 'superatom'. Rubidium atoms are bosonic so they move together but don't tend to stick together, so what actually happens to the atoms at temps close to abs zero that causes them to become a fermionic condensate.

2007-12-14 09:38:58 · 1 answers · asked by Trevor 7

In a test carried by a car manufacturer, a test driver is asked to put on his brakes when a warning light is suddenly flashed. When traveling 25 m/s the driver is able to stop in 50 m after slamming on the breaks. a. What is the car's acceleration?

Please show/explain all work. Please show what formulas were used.

2007-12-14 09:37:41 · 2 answers · asked by Kantilal P 1

What are the physical changes, on an atomic level, that something such as caesium undergoes when it is supercooled to the point of becoming a BEC. I know that it becomes a 'squiggle' but can anyone explain it in a little more detail. Thanks.

2007-12-14 09:32:46 · 1 answers · asked by Trevor 7

Please summerize volcanism

2007-12-14 08:58:33 · 1 answers · asked by Anonymous

2007-12-14 08:41:12 · 2 answers · asked by bluekiwi 2

[NOTE: the numbers in this problem are unrealistic, but are more simple to work with than a more realistic situation would be.]

When two masses, Mass A and Mass B, are 1.0 m apart, they exert a gravitational force of 1 N on each other. If Mass B is replaced by Mass C which is 200 times greater than Mass B, what will be the gravitational force between Mass A and Mass C?



Remember the equation Fgrav = (mass 1 ) (mass 2)

distance2



(For this problem Mass A = 1 kg, Mass B = 1 kg, Mass C = 200 kg)

Be sure you show how you arrived at your response

2007-12-14 08:13:51 · 3 answers · asked by Anonymous

Would an upside down conical shaped vessel heat faster than a cylindrical one?

Taking into consideration that heat rises and that the water is being heat from the bottom of the vessel.

All being the same, including volume of water and surface area of vessel and of course the size of heating element. Also assuming that heat loss is the same.

I'm pretty convinced that the conical shape would allow a quicker boil due to a more intensive heat lower down and the rising of the hotter water.

2007-12-14 08:04:59 · 4 answers · asked by britishbuddha 2

Assuming God is real, is it possible for Him to exist in an unknown dimension?

2007-12-14 07:56:41 · 2 answers · asked by Anonymous

Why do shadows always fall north along an East-West line? At least in the Northern Hemisphere. Would shadows fall south in the Southern Hemisphere? In what situation would a shadow fall south in the northern hemisphere??

2007-12-14 07:33:58 · 5 answers · asked by jiggly_puff_59 1

There are N=10e10 identical stars in a galaxy, mass of each star is M=10e30kg and rms velocity of stars is V=100 km/s.

How much energy is needed to disassemble the galaxy and scatter the stars (but not disasseble the stars themselves)?

2007-12-14 07:22:09 · 10 answers · asked by Alexander 6