Question

# Two blocks A and B of masses 2m and m, respectively, are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in the figure. The magnitude of the acceleration of A and B, immediately after the string is cut, are respectively g,gg,g2g2,gg2,g2

Solution

## The correct option is C g2,gFBD of A and B before cutting the string, For block B T=mg For block A kx=T+2mg Since T=mg ⇒kx=3mg Let the acceleration of block A and B be aA and aB. For block A, kx−2mg=2maA Since kx=3mg ⇒3mg−2mg=2maA ⇒aA=g2↑ For block B, mg=maB ⇒aB=g↓

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