To understand how to calculate forces between charged particles, particularly the dependence on the sign of the charges and the distance between them. Coulomb s law describes the force that two charged particles exert on each other (by Newton s third law. those two forces must be equal and opposite). The force F21 exerted by particle 2 (with charge q2) on particle 1 (with charge q1) is proportional to the charge of each particle and inversely proportional to the square of the distance T between them: where k = 1/4 pi epsilon 0 and is the unit vector pointing from particle 2 fo particle 1. The force vector will be parallel or antiparallel to the direction of parallel if the product q1q2 > 0 and antiparallel if q1q2 < 0: the force is attractive if the charges are of opposite sign and repulsive if the charges are of the same sign. A. Consider two positively charged particles, one of charge q0 (particle 0) fixed at the origin, and another of charge q1 (particle 1) fixed on the y-axis at (0, d1, 0). What is the net force on particle D due to particle 1? Express your answer (a vector) using any or all of k, qo, q1, d1, B. Now add a third, negatively charged, particle, whose charge is -q2 (particle 2). Particle 2 fixed on the y-axis at position (0, d2, 0). What is the new net force on particle 0, from particle 1 and particle 2? Express your answer (a vector) using any or all of k, q0, q1, q2,d1,d2 C. Particle 0 experiences a repulsion from particle 1 and an attraction toward particle 2. For certain values of d1 and d2, the repulsion and attraction should balance each other, resulting in no net force. For what ratio d1/d2 is there no net force on particle 0? Express your answer in terms of any or all of the following variables: k, q0, q1, d2 Part D (Figure 3) Now add a fourth charged particle, particle 3. with positive charge q2, fixed in the yz-plane at (0,d2,q2). What is the net force on particle 0 due solely to this charge? Express your answer (a vector) using k, q0, q3, d2, Include only the force caused by particle 3.