Question

Two point charges are located on the x-axis of a coordinate system: 𝑞_1 =-1.5 𝑛𝐶 is at 𝑥 = +4.0 𝑐𝑚, and 𝑞_2=−3.5 𝑛𝐶 is at 𝑥 = +2.0 𝑐𝑚. What is the total electric force exerted by 𝑞_1 and 𝑞_2 on a 𝑞_3= 2.0 𝑛𝐶 at 𝑥 = +3 cm?

Answer 1

$F=kq_3(\frac{q_1}{x_1^2}+\frac{q_2}{x_2^2})=2~\mu N.$