thsi will give u an idea how to solve the question
http://targetiit.com/iit-jee-forum/posts/min-h-1222.html
initially the spring was highly compressed such that b1 almost touched b2.suddenly the compressing force was removed.find m such that b2 jumps from the ground.(assume spring constant to be k)
thsi will give u an idea how to solve the question
http://targetiit.com/iit-jee-forum/posts/min-h-1222.html