Question

Consider charges placed along an x-axis. If a charge of +17 nC is placed at x = 0.00 m and a charge of +32 nC is placed at x = 1.00 m, where would a third charge of -14.0 nC be in electrostatic equilibrium? Give the x-coordinate for your answer in meters and with three significant figures.

Answer 1

It is obvious the charge must be in between the two positive charges.

force1=force2
17(14)/x^2=32(14)/(1-x)^2
or
17(1-x)^2=32x^2

then solve for x.