Need to find the EPE, electric field and the work of the charges

[joseernesto]

Homework Statement

consider two positive charge+Q at the upper corners of a square. two negative charges-Q are located at the lower corners.assume that each side of the square is S.
A) what is the total EPE of the array
B)what is the electric field at the center of the square?
C) how much work would the electric field perform on a charge q as it moved from the midpoint of the right side of the square to the midpoint to the top of the square?

Homework Equations

EPE= V/q
E=(K)(Q)(Q)/D

The Attempt at a Solution

 

[graphene]

Did you attempt the solution? What exactly did you do? Put down the steps here.