A point charge +2.0C is at the origin and a second point charge -3.0?C is at x = 50 cm.
1) Compute the potential at x = -50 cm and x = 40 cm.
2) discover the potential at a general point on the positive y-axis (take +y to be upward on your coordinate system).
3) Using the result of (b) find the potential at y = 40 cm.
4) Using the result of (b) find the electric field component along the y-axis.
5) Decide Ey at y = 40 cm.