Consider the situation of the previous problem. Suppose the block of mass m1 is pulled by a constant force F1, and the other block is pulled by a constant force F2. Find the maximum elongation that the spring will suffer.

Let F1 and F2 be the forces acting on the blocks of mass m1 and m2 respectively.


Spring constant is k.


Energy stored (E) in the spring will be



Acceleration of block of mass m1 will be



Acceleration of block of mass m2 will be



Due to F1 and F2 acting on blocks of mass m1 and m2, they will experience different acceleration and inertia.


Net force (N1) on m1 will be F1 – m1a1






Net force (N2) on m2 will be F2 – m2a2






If m1 and m2 displaces by x1 and x2 respectively then the maximum elongation in the spring will be x1+x2.


Now, work done by the blocks + energy stored in the spring





1