Practice Problem on Potential Energy for Point Charges



  Q1=-2 micro-C - o--------o Q2=-5 micro-C
                ^ |        |
                | |        |
            3cm | |        |
                | |        |
                | |        |
                | |        |
                v |        |
  Q3=-1 micro-C - o--------o Q4=-2 micro-C
                  |--2cm---|



4 charges are arranged on a rectangle as shown above. What is the potential energy of this charge configuration? Use the convention that U = 0 when the charges are infinitely apart. Specify your answer to three significant places.

ANSWER = ( U = 1.12e+1 J )