Physics - September 2006

A flat square sheet of thin aluminum foil, 25cm on a side carries a uniformly distributed 35nC charge. What, approximately is the electric field (a) 1.0 cm above the sheet and (b) 20m above the sheet?

Should I calculate the electric field
(σA)/ε0 which is: [(35*10^-9C)(.25m)^2] / 8.85*10^-12 = 2.5*10^2

If that is correct how do I find out what the field is at each distance.

Do I use the E=(kQ)/(r^2) formula? When using this it seems to generate a larger field at 1cm (3.15*10^6) than the field at the origin 2.15*10^2 and 20m gives 7.9 *10^-1.

Any help is appreciated...

2006-09-04 02:43:30 · 2 answers · asked by Anonymous

Than some one finds out that they were fairy tales after all because he discovered other facts that proved otherwise?

2006-09-04 02:29:16 · 4 answers · asked by goring 6

Than some one finds out that they were fairy tales after all because he discovered other facts that proved otherwise?

2006-09-04 02:28:14 · 2 answers · asked by goring 6

According to science no speed is greater than that of light. So the relative speed of the muons cannot be 0.9C+0.9C=1.8C since that will be greater than the speed of light!( where C is the speed of light)

2006-09-04 02:28:10 · 10 answers · asked by yacks 1

what was the name of Albert Einstein best friend
YURI .........
what is his full name

2006-09-04 02:27:20 · 2 answers · asked by Anonymous

i was just wondering how an electric thermos works, on how it's interior looks like when sectioned and how it boils the water and somehow traps the steam and heat for some time.. any site explaining to this might also help

2006-09-04 02:25:02 · 1 answers · asked by zil 1

When scientists split the atom did they just use any old atom or buy a special one?

2006-09-04 02:21:50 · 14 answers · asked by Anonymous

Is energy a process that can only be used,hence ist not a conversion but a squeezing out Process. Just like when you squeeze water out of a sponge?

2006-09-04 02:17:56 · 2 answers · asked by goring 6

2006-09-04 02:14:02 · 4 answers · asked by g-aNn 1

From my (limited) understanding of string theory it seems as though it's reliant on ideas such as multiple universes which are outside of what we can evidentially prove. Is this the case? And, if so how can we ever be sure that these ideeas are a true reflection of reality?

2006-09-04 01:30:41 · 15 answers · asked by Dan P 4

2006-09-04 01:02:00 · 15 answers · asked by Claude 6

In a certain region of space the electric field is constant in direction (say horizontally, in the x direction), but its magnitude decreases from E=560 N/C at x=0 to E = 410 N/C at x=30m. Determine the charge within a cubical box of side l = 30m, where the box is oriented so that four of its sides are parallel to the field lines.

The answer to this is -1.2 micro C. I have now idea how they got this answer. Any help is appreciated.

2006-09-04 00:48:16 · 1 answers · asked by Anonymous

WHAt would you do if:

1. You're caught in the middle of open field during a thunderstorm? (with no where to hide) WHY?

2. You're caught in a thunderstorm would you run into the forest or into the open field? WHY?

Thanks guys! I need the answers tonight ^^ God BLEss^^

2006-09-04 00:35:00 · 3 answers · asked by JaSmiNE 2

2006-09-03 23:55:41 · 23 answers · asked by RAJKISHORE B 1

Thanks to those that answer my guestion. Here's more infro about the problem. The ground does slope away from the well house (about 200 yds.) before it drops down the hill. I suggested putting in a inline 20 ft section of 3" pipe just at the point where the ground starts to drop off down the hill. Putting in a pressure switch with a higher cut-in and shut-off might be the best option if I knew where to get such a item (or if those do exist). A 40/60 pressure switch is the highest setting switch that I can find around here.

2006-09-03 23:51:14 · 3 answers · asked by motreefarmer 1

2006-09-03 23:44:57 · 9 answers · asked by Saif U 2

2006-09-03 23:38:02 · 14 answers · asked by abdulkam 2

i added a lot of added details to this qn and i would those issues addressed too thanks:
http://answers.yahoo.com/question/index;_ylt=Av6Z_BgpfG.YdQXnvDCF5__sy6IX?qid=20060904030314AA0Uqn2

2006-09-03 23:20:08 · 1 answers · asked by lazydazy 4

could the 3rd theory be like a mixture of the 2 or creationism but without the story of adam and eve or creationism without god... could evolution actually not be progressive but ever changing... ie we dont necessarily evolve into better beings but the earth is actually in different states of flx depending on how we treat it.. (ie the butterfly effect if you know what i mean)..

2006-09-03 23:03:14 · 12 answers · asked by lazydazy 4

a.) albert einstein
b.) isaac newton
c.)charles babbages

2006-09-03 22:48:03 · 13 answers · asked by Anonymous

I have been told that the water pressure in a water line can be increased by installing a 20 - 30 ft section of a larger diameter pipe in the existing water line. I can see where it could be like installing a 'pressure tank' inline, but does it really work? I ask because my son brought a place where the well house is 1/4 mile from the house. The line to the house is 1 inch pvc. To make matters worse, water line goes down and back up a hill (approx. 60 ft fall, 70 ft rise). At the well house, the pump kicks off at 60 psi. At the house, water pressure is about 44 psi at the faucets. He doesn't want to put in a 1 1/2" water line. He was told about putting in a secton of larger pipe by a 'old timer' who installed water lines all of his adult life. The gentleman swears that it will work because he has done it before on numerous occassions.

2006-09-03 22:29:06 · 6 answers · asked by motreefarmer 1

2006-09-03 22:16:31 · 63 answers · asked by aman b 1

Which of the following is more likely to scald you?
(i) Water at 100 degrees celsius
(ii) Steam at 100 degrees celsius
Explain your answer.

2006-09-03 22:15:18 · 24 answers · asked by noob 1

2006-09-03 21:59:28 · 27 answers · asked by Mr. Clueless 1

2006-09-03 21:58:23 · 5 answers · asked by w c 1

2006-09-03 21:57:46 · 23 answers · asked by Anonymous

in a woman's open mouth?

2006-09-03 21:52:04 · 6 answers · asked by Anonymous

2006-09-03 21:41:28 · 1 answers · asked by Spadesboffin 3

2006-09-03 21:13:40 · 3 answers · asked by Michael K 2

I forgot my husband home...what should i do?

2006-09-03 21:11:31 · 16 answers · asked by rekha c 3