Figure shows two block `A` and `B`, each having a mass of 320 g connected by a ligh

Figure shows two block `A` and `B`, each having a mass of 320 g connected by a light string passing over a smooth light pulley. The horizontal surface on which the block `A` can slide is smooth. The block `A` is attached to spring constant `40 N//m` whose other end is fixed to a support 40 cm above the horizontal surface. Initially, the spring is vertical and unstretched when the system is released to move.