Q: Two blocks of masses m and 2m are connected through a wire of breaking stress S passing over a frictionless pulley. The maximum radius of the wire to be used so that the wire may not break is

(a) $ \displaystyle \sqrt{\frac{3 m g}{4 \pi S}} $

(b) $ \displaystyle \sqrt{\frac{4 m g}{3 S}} $

(c) $ \displaystyle \sqrt{\frac{4 m g}{3 \pi S}} $

(d) $ \displaystyle \sqrt{\frac{ m g}{2 \pi S}} $

Ans: (c)