Two point charges are fixed on the y axis: a negative point charge q1 = -26 µC at y1 = +0.21 m and a positive point charge q2 at y2 = +0.38 m. A third point charge q = +8.5 µC is fixed at the origin. The net electrostatic force exerted on the charge q by the other two charges has a magnitude of 24 N and points in the +y direction. Determine the magnitude of q2.
Set the sum of the Coulomb forces on q equal to 24 N (in +y direction) , and solve for the only unknown, q2.
The force due to q1 is up (+y direction) and the force due to q2 is down.
k(8.5*10^-6)*[26*10^-6/(0.21)^2 -q2/(0.38)^2] = 24
k is the Coulomb constant.posted by drwls