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

Options

A. `sqrt((3)/(4)(mg)/(pi S))`
B. `sqrt((4)/(3)(mg)/(S))`
C. `sqrt((4)/(3)(3g)/(pi S))`
D. `sqrt((1)/(2)(mg)/(pi S))`

Answer

C

Explanation

Stress, `S = (T)/(pi r^(2))`, herer `T-mg = ma`............(i)
`2mg - T = 2ma`..........(ii)
On solving `T = (4)/(3)mg` then `S = (4mg)/(3pi r^(2))`