I went through some old files and found one article that I wrote when studying the controlled demolition theory. I wrote it to myself and it does not have much new to anybody, who knows this topic, but I noticed that it had a calculation. I was unconvinced by David Chandler’s simple argument for the impossibility of the free fall acceleration. There were people, who claimed that if the building pancakes, it can fall like that. So, I made this kind of a calculation and it lead to another problem: no energy to pulverize the cement. The calculation is the reason why I put this article to this post. Here it is: