Chapter 21, Problem 21.66P

Point charge q₁ = −6.00 × 10⁻⁶ C is on the x-axis at x = −0.200 m. Point charge q₂ is on the x-axis at x = +0.400 m. Point charge q₃ = +3.00 × 10⁻⁶ C is at the origin. What is q₂ (magnitude and sign) (a) if the net force on q₃ is 6.00 N in the +x-direction; (b) if the net force on q₃ is 6.00 N in the −x-direction?