Not saying you’re wrong - you’re probably right. But as an engineer, I’ve referred to or been asked about “the center of mass” thousands of times and not once have I ever heard “virtual” used. It’s just always the center of mass - wherever that point exists in all of spacetime.

It’s weird. Did something change over the years (like using the Oxford comma or double spacing after a period?). Or is that something that’s always been a thing that I’ve never run across? Strange ;)