Four long, straight, horizontal conductors labeled A, B, C, and D are fixed in the…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
Four long, straight, horizontal conductors labeled A, B, C, and D are fixed in the same horizontal plane. The wires are arranged left-to-right with equal center-to-center separations of 5.0 cm. Wire A carries 3.0 A toward geographic north, wire B carries 5.0 A toward geographic south, wire C carries 3.0 A toward geographic north, and wire D carries 5.0 A toward geographic south. Ignore all fields other than those produced by the four wires themselves.
(a) For each adjacent pair of wires (A–B, B–C, C–D), state whether the two wires attract or repel one another. Justify each answer by discussing both the direction of the magnetic field produced by one wire at the location of the other and the direction of the force that results.
(b) Considering the magnetic forces exerted by all the other wires, determine the direction (left, right, or zero) of the net horizontal magnetic force acting on wire B. Provide a clear explanation of your reasoning.
(c) Suppose the wires are free to slide horizontally on frictionless supports. Describe qualitatively the subsequent motion of each wire and explain how the pattern of motion is consistent with Newton’s third law.