Lol, you been raiding the CIA files again Mick
Good perspective.
But seriously, there must be a formula like Newton's Third Law that covers this.
It's like in martial arts... if you punch an object very hard but it does not give, (say a car window), you will likely damage your hand... but if you punch with enough force to breakthrough the window, you will hardly feel it. It is almost as if there was nothing much there.
Using this fact, there must be studies whereby objects of differing mass have been dropped from varying heights onto objects with varying but known, strength and a formula derived.
i.e. say a bowling ball 'm', dropped from 150' onto 10 glass sheets 'g' with 15' in between each.
Finding how much weight 'm' is slowed from normal gravity acceleration, or it may even get to glass sheet 5 and not pass through because of lack of force, much like a bullet coming to rest in ballistics gel.
The other point I would make, is as the top broke up, 'dustified', what impacted the lower part of the towers was technically a dense 'fluid' containing larger solids.
Also, there should be some info on the maximum weight possible of the aggregated 'dustified' top section which was impacting the lower section, taking into account ejecta and 'overflowing'.
Just wondered if your CIA banks ran to that sort of info
I just made that image from a youtube video. It's a "cinemagraph", they are very easy to make.
There are certainly formula that cover this, but not one simple one. The problem is that "damage" is not a simple quantity. Consider impact analysis in car crashes. One might say that it's a simple problem - a car travelling at 30 mph hits a tree. And yet the end result will vary radically based on which type of car you are in. It's actually a very complex problem, one that is not solvable by simple equations like "F1 = -F2". It requires a simulation to see what really happens, and the technique most often used is finite element modeling.
Newton's third laws says that "for every action there is an equal and opposite reaction". If you push something it will push back. If you stand on ice and push someone of equal weight, you will move away from each other.
But if you take a thin steel rod and rapidly bend it in two over your knee, then what exactly is the applicability of Newton's law? Did the rod push back, sure it pushed back against your hands, and against your knee. But a portion of the force went into breaking the molecular bonds in the middle of the rod, hence softening it, bending it, and heating it up. That's why Newton's laws cant really describe what is going on, because they say nothing about molecules, and deformation, and heat.
To your example with the bowling ball. That is something that you could probably make a good estimate of, if you have a good understanding of the materials involved. It's not simply mass we are talking about, it's also hardness and shape. Five pounds is not just five pounds of force. It's how it impacts, and over what period. A five pound iron ball will be very different to a five pound water ballon, and very different to a five pound rubber ball. and a five pound cube will have a different effect if you drop it on its point or on its side. It will also made a difference if you drop it in the middle, or at the edge by a support.
So it's quite complicated to do using equations of motion - which is why attempts to do so usually make overly simplistic assumptions, and don't account for what is actually happening. The most common mistake is failure to distinguish between static forces (simple weight, the force of thirty pounds held by your hand) and dynamic forces (the much more complex force exerted in a collision, such as the force of a thirty pound weight falling on your hand from thirty feet up).
So we usually discuss such things in terms of energy. Energy is measured in joules, there are different forms of energy: potential, kinetic, heat, sound, chemical, electric, etc. Here were are mostly concerned with the first four. We know how much energy is in the top part of the building (and in each floor below it). We know how much energy gets converted from potential to kinetic when it drops so many floor. We can estimate how much energy it takes to destroy a floor (to buckle all the columns to the point of failure). We can then simply add up the energy as we go, and see if it matches the observations.
Of course this is still a simplification. There are many unknowns, and sever assumptions. The columns might, for example, buckle over longer lengths than a single floor. The floors might be stripped away before or after the buckling. Some columns might not buckle at all, but spear through for a few floors.
But we can at least get some baseline worst case estimates.
The dispute then falls into three camps. On the one had we have people who say that Newton's Third Law is broken, and this energy talk is bunk. With them we can only try to explain why Newton does not really apply. Secondly we have people who just dispute the energy requirements, and there we need to drill down to try to find why the estimates differ. Finally you have people who have a whole other theory entirely, usually based on some rather dodgy physics.