Answer:
U = 80.91 J
Explanation:
In order to calculate the electric potential energy between the three charges you use the following formula:
(1)
k: Coulomb's constant = 8.98*10^9Nm^2/C^2
q1: q2 charge
r1,2: distance between charges 1 and 2.
For the three charges you have:
(2)
You use the fact that q1=q2=q3=q and that the distance between charges are equal. Then, in the equation (2) you have:
q = 1.45μC = 1.45*10^-6C
r = 0.700mm = 0.700*10^-3m
The electric potential energy between the three charges is 80.91 J