Reply #32: If it starts out tipping, it will continue tipping...

[janedoe]

...unless acted on by an external force.


Compare stresses

The only way for the top chunk to rock to the right, then the left, might be if the core was still intact and acted as a pivot point, but it would still require an outside force to change the direction of it's momentum. Example: a playground see-saw (or teeter-totter). The kid on the end that's moving down needs to push off the ground to start moving back up.

Assuming a "natural collapse," (i.e. without explosives):
If the core is gone and the building tips (rotates) to the left, the left side was weaker than the right. Now that it has tipped, there is even less load on the right side than before the tipping. So, with less load on it, why would it fail?