Four point charges are located at the corners of a square with sides of length a. Two of the charges are +q, and two are -q. Find the magnitude and direction of the net electric force exerted on a charge +Q, located at the center of the square, for each of the following arrangements of charge: (a) The charges alternate in sign (+q, -q, +q, -q) as you go around the square (b) the two positive charges are on the top corners, and the two negative charges are on the bottom corners.
Can someone please EXPLAIN the problem. I don't understand barely anything about the problem other than it is symmetrical because its a square. But how do we work this out, not just say each charge is canceling the other. I don't understand the (a/2)^2 or the vector aspect of the problem, hence cant work the problem at all.
1 answer
Each of the 4 contribute to the whole. For example the q+ charge in the upper left pushes the Q+ charge towards the lower right corner. The magnitude is kqQ/r^2. r is a sqrt(2)/2. Do the same for the other 3 charges and sum the vectors when you are done.
1 answer