Answer: Ue = 2.17x10^-8 N*m
Step-by-step explanation:
The equation for the electric potential charge is:
Ue = k*q1*q2/r
where q1 and q2 are the charges, k is a constant k = 9x10^9 N.m^2/C^2
Here we have coulombs, and in the charges we have nanocoulombs, so we need to do a change of units.
q1 = 5.1 nC = 5.1x10^-9 C
q2 = 2.6 nC = 2.6x10^-9 C
and r is the distance between the charges, in this case r = 5.5m
Then we have:
Ue = (9x10^9 Nm^2/C^2)*(2.6x10^-9 C)*(5.1x10^-9 C)/5.5 m
Ue = (9*5.1*2.6/5.5)x10^-9 N*m
Ue = 21.7x10^-9 N*m
Ue = 2.17x10^-8 N*m