Two blocks A and B of masses 2m and respectively, are connected by a massless and inextensible string. The whole system is suspended by a masslessspring as shown in the figure. The magnitude of acceleration of A and B, immediately after the string is cut, are respectively

Options

A. `g,(g)/(2)`
B. `(g)/(2),g`
C. `g,g`
D. `(g)/(2),(g)/(2)`

Answer

B

Explanation

just before the string is cut force on the spring pulling up` = kx = 3mg `
After string is cut , free body diagram of block A is as shown in figure (i)
` or a_A = (mg)/(2m) = (g)/(2)`
free body diagram of block B as shown in figure (ii )
` therefore ma_B = 3 mg - 2mg `
` or a_B = g`