Hey I'm a new time member but I hope to use this forum for my college Physics 2 class, anyways: 1. Question: Two charges are D = 2.5 m apart and lie on the x-axis. What must be the magnitude of the charge on the right one, Q2, (in C) so that the electric field is zero at x = 1.75 meters. Let Q1 be at the origin and have a charge 17 C. 2. Equations I'm using. E(total)=E1+E2... E=k*q/r^2 3. My attempt: E1=(8.99E9)(17C) / (1.75^2) = 4.990E10 E2= k*Q / (1.75^2) E(total) = E1 + E2 0 = E1+E2 -E1=E2 Q= (-4.990E10)(1.75^2) / (8.99E9) Q= -16.9987 I've just learned electrical fields / coulombs law, for a problem like this I just need some explanation on what I'm doing wrong. I thing what the biggest problem is and confusing this is it initially is 2.5m apart but they want you to find it at 1.75m, I'm going to keep working but I feel like the 2.5 is relevant and I'm not using it. Thanks in advance.