After release from rest at B, the 2-lb cylindrical plug A slides down the smooth path an...

After release from rest at B, the 2-lb cylindrical plug A slides down the smooth path and embeds itself in the 4-lb block C. Determine the velocity v of the block and embedded plug immediately after engagement and find the maximum deflection x of the spring. Neglect any friction under block C. What fraction n of the original energy of the system is lost?