the instant the upper 13% destroys the floor below it, that floor becomes part of the falling destructive mass and the percentage of the upper tower falling onto the next floor rapidly increases.
And the Conservation of Momentum does not apply and no energy is lost breaking supports.
And you will of course demonstrate how the energy added by the additional collapsing mass is less than the energy lost due to impact resistance.
dang I promised myself not to post here again, but given Walper’s interesting posts, I can’t resist.
I’ll bet a few of us would be interested in hearing psik’s answer.