AP PHYSICS test tomorrow. poop. (help please?)

[Jittles]

God I'm dumb. I cannot for the life of me remember how to do this problem. Anybody care to tell me how?

+Q______-Q
---|---------|
---|---------|...s
---|---------|
.-Q______+Q
..........s........

A square with sides "s" and each particle in the corners with equal charge "Q" although positive and negative.

Find the electric potential at the center of the square.

So V = kq/r but I don't know how to add them together and whatnot? Please help! the r is going to be what? root(2)/2?

UGH.

Next find the magnitude of the electric field in the center.

No clue.



There is a cylinder fitted with a freely moving piston of area 1.2 * 10^-2 m^2 and negligible mass. In state 1 the gas has volume 1.5 * 10^-3 m^3, pressure 1.02 * 10^5 Pa, and the temp is 0 C.

A 2.5 kg metal block is placed on the top compressing the gas.(STATE 2) The cylinder is then put in boiling water and brought to 100 C.(STATE 3)
The block is removed and temp stay at 100 C (STATE 4)

Determine pressure of the gas in state 2
""""""""volume in state 2

state 2 -> state 3 is: isothermal, isobaric, or adiabatic?

Determine volume of the gas in state 4



I hope there is somebody out there to lend assistance to me! heeeeeeeeeeeeeeeeeelp!

THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU.

 

[Michael1897]

step one: put head between legs
step two: kis your @ss good-bye

good luck

 

[Kadarin]

After my first glance of the thread title, I thought you had an AP physics test that had something to do with feces.. silly me! Good luck!

 

[Jittles]

Originally posted by: Michael1897
step one: put head between legs
step two: kis your @ss good-bye

good luck

Thanks. Good advice. I spent about an hour and a half consoling my girlfriend and it ruined my studying time. that BITCH. (3rd rock from the sun, dick's style)

 

[dafatha00]

have fun man. if you're not ready for the test by now, you won't be tomorrow. ap physics test is a killer. which one are you taking?

 

[Jittles]

B

 

[Jittles]

OK got the first one.

Anybody?

 

[Jittles]

Eh. Screw it I'm goin to bed. good night sleep more important than last minute cramming.

 

[lawaris]

starting from the LHS top corner.............

each charge is sqrt.2/ 2 dist. away from the centre.
That fixes r

Now, join all 4 to the centre of the sq.

Directions are fixed in this way. Arrow goes towards the neg. charges and away from the positive charges.

Cal. the pot. doe to each of them and all them using vectors algebra.

To cal. Elect. filed :

Use E = V/d.


hope that helps