I'm in strict pedant mode today.

1. It still isn't free fall. The acceleration of the object will depend on its shape.

2. An explosive charge will have some upward force component and the debris and expanding gas beneath the object will have a different composition from the air under the other mass, so its behaviour will be different depending on the nature of the trigger event.

3. Where did the second mass come from? Something must have been holding it up before the explosion!

I appreciate your pedantry.... You're a way out cat man (complimentary)!I see your point.... Would it be reasonable to say though in just a general every day terrestrial sense, that the effect any aerodynamic properties might have on the 100 pound weights fall time (being a relatively compact object) falling from a height of 15 feet could be considered negligible, or do we need to switch to an in vacuo environment to eliminate it as a concern? I don't have any preference.Understood.... Do you think though for the time being, we could just assume a carefully engineered charge whose total upward force (the explosion, the expanding debris and the expanding gas components combined) is equal to 100 pounds so that it wouldn't lift the weight in the process of destroying the column? Just to render it negligible for the sake of general discussion.I think the weight that appears on the right (they're just general schematic animations) just as each scenario begins to unfold would be what you science guys call a "control" meant to be held up as a standard, or visual aid, to compare various possible scenarios (on the left) and generally illustrate what could reasonably be expected to occur compared to an identical control (on the right) under identical conditions at the same time....The falling weight on the right is the same in all the animations. Does that make sense? I sort of described it earlier....