1. The problem statement, all variables and given/known data Particle 1 of charge +4.0 μC and particle 2 of charge +1.0 μC are held at separation L=10.0 cm on an x axis. Particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero. In the included figure, particle 1 is located at the origin and particle 2 is located 10 cm to the left on the x axis. 2. Relevant equations E=kq/|r|2 * r hat Enet=E1+E1 F=E*q 3. The attempt at a solution I thought that if the net electrostatic force is zero, then Enet must be zero. So the two electric fields created by particle 1 and particle 2 must cancel each other other. Following that thought: E1=q1*k/|r1|2 * r1 hat E2=q1*k/|r2|2 * r1 hat r1 = robservation - rq1 r1 = <x,0,0> |r1|=x r1 hat= <1,0,0> r2=robservation - rq2 r2=<x-0.10,0,0> m |r2|=x-0.10 r2 hat = <1,0,0> Enet=E1+E2 0=E1+E2 E1=-E2 k*q1*r1 hat/x2 = k*q2*r2hat/(x2-0.20x+0.01) After simplifying: x=[(-q2/q1)-0.01]/-0.20 x=1.3 m However this answer does not solve the problem or make sense. I was thinking that in order for the two electric fields to cancel each other out, the third particle should be placed in between the two particles, closer to the more weakly charged. I've played around with these equations several times and still can't figure it out. Thank you in advance for any help, and I apologize for any formatting errors.