일반물리학 2 — Electric Fields: Problem 16

16 Two charged particles are attached to an x axis: Particle 1 of charge $-4.00 \times 10^{-7}\text{ C}$ is at position $x = -5.00\text{ cm}$ and particle 2 of charge $+4.00 \times 10^{-7}\text{ C}$ is at position $x = 10.0\text{ cm}$. Midway between the particles, what is their net electric field in unit-vector notation?