An unknown additional charge q3 is now placed at point B, located at coordinates (0 m, 15.0 m ). Find the magnitude and sign of q3 needed to make the total electric field at point A equal to zero.

The first part of the question is:

Two point charges are placed on the x axis. (Attached file)The first charge, q1 = 8.00 nC , is placed a distance 16.0 m from the origin along the positive x axis; the second charge, q2 = 6.00 nC , is placed a distance 9.00 m from the origin along the negative x axis.

q3 = +0.3nc

Explanation:

Due to the vector symbols in the solution, I've decided to attach the explanation to this answer.

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