Three charges are -4.0 mC is at (4,-3), 2.0 mC at (3,-4)and a charge of -2.0 mC is at (- 3,4) [coordinates are in m], what is the absolute potential at the origin of the system?

Expert Answers
gsenviro eNotes educator| Certified Educator

For a 3 charge system, with given coordinates we will calculate the absolute potential at the origin (0,0) due to each of them and then obtain algebraic sum of all these potentials to get the desired result.

Absolute potential at origin due to charge 1:

V1 = ke x q1/distance = (8.988x10^9) x (-4 x10^-3)/(sqrt(4^2 + (-3)^2)) = -7.19 x 10^6 V

Absolute potential at origin due to charge 2:

V2 = ke x q2/distance = (8.988x10^9)x(2x10^-3)/(sqrt(3^2+(-4)^2))= 3.60 x 10^6 V

Absolute potential at origin due to charge 3:

V3 = ke x q3/distance = (8.988x10^9)x(-2x10^-3)/(sqrt((-3)^2 +4^2)) = -3.60 x10^6 V

The net absolute potential at the origin of the system due to these 3 charges is the algebraic sum of all the absolute potentials:

Vnet = V1+V2+V3 = -7.19 x 10^6 V