A horizontal turntable spins at a constant angular velocity $\omega$. A small block $A$ of mass $m$ is placed on the turntable at a distance $R$ from the center. The coefficient of static friction between block $A$ and the turntable is $\mu_s$. A second small block $B$, also of mass $m$, is placed at a distance $2R$ from the center, such that the center, block $A$, and block $B$ lie along a single straight line in that order. Block $B$ rests on a frictionless patch of the turntable. The two blocks are connected by a light, inextensible string of length $R$. What is the minimum value of $\mu_s$ required so that the blocks do not slide relative to the turntable? (Answer in terms of $\omega$, $R$, $g$)