Two blocks of masses `m` and `2m` rest on a frictionless horizontal surface. They are connected by an ideal spring of relaxed length `l` and stiffness constant `k`. By means of a massless thread connecting the blocks the spring is held compressed to a length `l//2`. the whole system is moving with speed `v` in a direction perpendicular to the length of the spring. the thread is then burnt. Answer the following questions in terms of `l,km,v`
After burning the string the speed of centre of mass is :
A. less than `v`
B. greater than `v`
C. equal to `v`
D. eqaul to `(2)/(sqrt3)v`
