# AP Electronics

1. Feb 22, 2008

### Chyea

1. The problem statement, all variables and given/known data
http://s241.photobucket.com/albums/ff121/JaguarJaguar/?action=view&current=chap16cw.jpg

2. Relevant equations
I don't have a clue as to where to start

3. The attempt at a solution
2 + 2 = 9... no but seriously, i hope i'm in the right forum because I need a lot of help with this problem. I just hope i came to the right place.

2. Feb 23, 2008

### blochwave

Technically I guess this is intro physics, by advanced they mean like quantum mechanics and advanced mechanics and E&M and the like, so they might move it but I don't think anyone cares really

Well let's start with 1) I'm not sure how much work it wants you to do. You could answer it like "Charge 1 is ____er than charge 2", or you could actually do the math and say "Charge 1 is ____times charge 2" but since you're apparently uncomfortable with the problems let's do both for practice, and just to make sure you get the right answer

So if I gave you two charges and said "the point where E=0 is exactly halfway between them" could you tell me how the charges compared to each other? If I move that point closer to one charge or the other, what's that say?

As for the actual math approach, you have an equation for what? The electric field strength of a charge Q at a distance r from it. You have two charges. You have a point a distance away that you're examining (if you call the distance between them D, it's 1/3 of D for Q1 and 2/3 D for Q2)The final thing to keep in mind is that one of the electric fields is negative, and one is positive. You know this because in between them the electric field will be pointing opposite directions. It doesn't really matter which you call positive or negative, but make sure that one is. Problem 2 is an extension of this

3. Feb 24, 2008

### Chyea

well, thanks, but the thing is due tomorrow, i don't have a lot of time for cross-referencing, I'll get help from a buddy in a study hall. thanks anyway.