<p>can anyone either help me solve a previous ap physics problem or help me find the solution for it? i am talking about the 2001 ap exam:</p>
<p>im talking about the problem with the four charges set up in a scale (number 3). specifically how do you solve for a ii. and b ii.? I got 0 volts for a i. and b i. but I cant think of any equation to solve for the magnitude of the electric field.</p>
<p>bump can someone plz answer my question??</p>
<p>ok look its really simple ..all you have to do is find the magitude of the electric field due to each charge at the center, and then add them using vector addition techniques, in the first one, you can logically determine that the answer is going to be zero because there are two pairs of opposite vectors with the same magnitude and they cancel out. in the second one however this is not the case becasue they dont cancel out ( the y components do though) . so you must first find the MAGNITUDE of the electric field due to each using the equation E=kq/r^2 and knowing that its a squre u know the diagonal is s*sqrt(2) so you take half of that to be the distance, r. then after that u just add the fields using vector addion, knowing that the angle they make with the horizontal is 45 ( 90/2, intersection of diagonals of square.)</p>