The string between blocks of mass m and 2m is massless and inextensible. The system is suspended by a massless spring as shown. If the string is cut find the magnitudes of accelerations of mass 2m and m (immediately after cutting)

Options

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

Answer

B

Explanation

After string is cut, free body diagram of block `A` gives
`2ma_(A)=3mg-2mg` or `a_(A)=(mg)/(2m)=(g)/(2)`
Free body diagram of block `B` gives
`ma_(B)=mg` or `a_(B)=g` .