Comment: This would be a tough one to determine

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This would be a tough one to determine

Since the lid could have flown several hundred feet in the air and landed on the roof on its way down. Since it is on the roof it must have been a parabolic so that the end of its trajectory had some kind of downward component. Since the lid landed on a roof close by, it had to have more of a vertical trajectory. This is because any mostly horizontal trajectories would travel large distances before dropping, or dropping to the ground initially without going up to roof level first.
Without knowing its path in more detail, but if you could characterize its path, calculating the exact force that launched it is easy, assuming you know its mass.

Another component possibly worth looking at is to determine the force required to rip the pressure cooker apart. This could be used to calculated a minimum explosives weight that it contained.

It would only be useful to determine what kind of explosives could have produced the blast we saw, given the limited volume of the pressure cooker. (Although I have a feeling that the list of explosives possible would be long, so not worth it). Or vice verse, knowing the type of explosive used, determine the space required to house it.