Unit is m^3 or metres cubed. You need to multiply the three dimensions of the block to get the volume.
A ruler can be used to measure the edges.
Most likely it would dislodge the coconut on the way down due to gravity because on the way up the gravity would slow down the rock but on they down the gravity pulls the rock
Compression and rarefaction are two phenomenon occurs in longitudunal wave!
when there is denser particle gathering in that wave , there we called it compression and the rarer part of particles is rarefaction !