Solve this:
A system consists of two cubes of masses m1 and m2 respectively connected by a spring of force constant k. The force (F) that should be applied to the upper cube to keep it at rest for which the lower one just lifts after the force is removed is?
A) m1g (C) (m1 + m2)g
(B) (D)m2g
When the spring bounce back again it's force equal to total weight hence (m1+m2)g is correct
