Question #43025

An infinitely long straight wire carrying a constant current $I_1$ in the $+z$ direction is fixed along the $z$-axis. A uniform rigid rectangular wire loop of total mass $m$, width $a$ (along the $x$-axis), and height $h$ (along the $z$-axis) is placed in the $x$-$z$ plane. The loop rests on a horizontal rough surface ($x$-$y$ plane) and is constrained to remain in the $x$-$z$ plane. The inner vertical edge of the loop is at a distance $d$ from the infinite wire. A current $I_2$ is gradually increased in the loop such that the current in its inner vertical edge flows in the $+z$ direction. What is the minimum coefficient of static friction $\mu$ between the loop and the surface required such that the loop topples before it begins to slide?