Not true since the debris was mostly small pieces not to mention that the concrete was pulverized before it even hit the ground. So no matter how fast it fell it would have not had much energy. Look at it this way, if you dropped a brick from a 100 story building or 100 bricks it still would be the same since you can not combine all their force since they are not attached.
You have anwsered your own question,would the brink completly break up ? Yep.
I want to understand,lets assume this was a consipercy.Then what made the it pulverize? Bombs? Iron weights?
Bomb will just explode it,no more wieght is needed that was a huge ass building.I fail to see your point.
BTW let me give you some food for thought,at the first golf war Iraq launced some Scud misslies with concrete heads in them.The energy caused a small earthquake that was detected quite far from the point of impact.
Sure a Scud is faster then a jet but it weigh WAYYYYY less,Im sure the plane had more energy.