Consider the following charge configuration: Three equal, positive charges +q are positioned at the three corners of a square (with side length a). 1. If you would like to bring in a fourth charge +q from infinity to place it on the fourth corner, how much work do you need to do? 2. How much work does it take to assemble the whole configuration of four charges?

Consider the following charge configuration: Three equal, positive charges +q are positioned at the three corners of a square (with side length a). 1. If you would like to bring in a fourth charge +q from infinity to place it on the fourth corner, how much work do you need to do? 2. How much work does it take to assemble the whole configuration of four charges?