A 750 mm long spring (k= 25 kN/m) is compressed and confined by a plate P, which can slide freely along the vertical 600 mm long rods. The 40 kg block is given a speed of v= 5 m/s when it is h= 2 m above the plate. Determine how far the plate moves downwards when the block momentarily stops after striking it. Neglect the mass of the plate.