일반물리학 2 — Coulomb's Law: Problem 8

8 In Fig. 21-12, particles 1 and 2 are fixed in place on an x axis, at a separation of \(L = 6.00 \text{ cm}\). Their charges are \(q_1 = +e\) and \(q_2 = -27e\). Particle 3 with charge \(q_3 = +4e\) is to be placed on the line between particles 1 and 2, so that they produce a net electrostatic force \(\vec{F}_{3,net}\) on it. (a) At what coordinate should particle 3 be placed to minimize the magnitude of that force? (b) What is that minimum magnitude?