A 35 kg block is attached to a spring of stiffness $1.7\times 10^5N/m$. Coefficient of friction between the block and surface on which it slides is 0.11. The block is displaced 10 mm from equilibrium and released i) what is amplitude of motion at the end of first cycle? ii) How many cycles of motion occur? Also find the number of cycles corresponding to 50% reduction of its initial amplitude.