Three long, straight conductors form the vertices of an equilateral triangle of side…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
Three long, straight conductors form the vertices of an equilateral triangle of side length 0.20 m. Wires 1 and 2 carry identical currents of 8.0 A into the page. Wire 3 carries a current I3out of the page.
(a) Derive an expression for the net magnetic force per unit length acting on wire 3 in terms of I3, the given numerical values, and fundamental constants. Show all steps in your reasoning.
(b) Determine the magnitude and direction of I3 that will make the net magnetic force on wire 3 equal to zero.
(c) Discuss whether the equilibrium found in part (b) is stable or unstable. Support your answer with qualitative arguments based on how a small displacement of wire 3 would influence the forces acting on it.