A tray of mass $$12 \mathrm{~kg}$$ is supported by two identical springs as shown in figure. When the tray is pressed down slightly and then released, it executes SHM with a time period of $$1.5 \mathrm{~s}$$. The spring constant of each spring is

A piston is performing S.H.M. in the vertical direction with a frequency of $$0.5 \mathrm{~Hz}$$. A block of $$10 \mathrm{~kg}$$ is placed on the piston. The maximum amplitude of the system such that the block remains in contact with the piston is