Three point charges are arranged along the x-axis. Charge q1 = -4.00 nC is located at x = 0.250 m and charge q2 = 2.00 nC is at x = -0.330 m. A positive point charge q3 is located at the origin.
(A) What must the value of q3 be for the net force on this point charge to have a magnitude of 3.50 μN? Express your answer in nanocoulombs.
(B) What is the direction of the net force on q3?
+ x direction
- x direction
(C) Where along the x-axis can q3 be placed and the net force on it be zero, other than the trivial answers of x = +∞ and x = −∞? Express your answer in meters.