A couple of times recently I've seen the term "passive force".
I've never been entirely sure what that meant. I reckon it
is something akin to a force of constraint.
Questions:
1) If there are really two ideas here, rather than one idea
going by two different names, what are the ideas? What
is the distinction between the two ideas?
2) If there is just one idea here, is there any reason to
prefer one terminology over the other? Based on what
little I know at the moment, I would tend to favor
"force of constraint" on the grounds that it is more
descriptive and more conventional ... unless somebody
has a good counterargument.