physics
posted by matt .
Please Help,
Two point charges are fixed on the y axis: a negative point charge q1 = 23 µC at y1 = +0.23 m and a positive point charge q2 at y2 = +0.33 m. A third point charge q = +7.8 µC is fixed at the origin. The net electrostatic force exerted on the charge q by the other two charges has a magnitude of 29 N and points in the +y direction. Determine the magnitude of q2.

Add up the two forces acting on q, using the Coulomb equation for the forces due to q1 and q2, and solve for the only unknown, q1.
The force due to q2 acting upn q is up (+y)and the force due to q1 on q is down (y).
Show your work if further assistance is needed.