The response to my second question included a link to an article that suggests all numbers (including natural and whole numbers) are in fact human constructs and may be considered imaginary. That is an enlightening insight that would help us both stop thinking of the words "negative" and "imaginary" as perfectly well defined in our heads. Those words are just tools that can help us convey the most appropriate meaning for the context.
Without the link to the article, that hypothetical conversation probably would not have worked out as well.
I think it should have told you it's called complex numbers, because they are composites.
not really your point, but ??
a decelerating car has negative acceleration, and until it starts reversing relative to its start, it has velocity in whichever direction it started in -- presumably positive if that was your initial frame of reference. of course if you decided positive was the opposite direction from which the car was already going in, well, it started with negative velocity.
also to the GP, if you owe someone a sheep but don't have any, you really do have -1 sheep.
- A decelerating car does not have negative velocity
- "negative velocity" is assuredly nonphysical, which rips the middle out of an argument based on physicality
- Velocity is a vector quantity, as is acceleration. (the steelman'd version of this argument is s/velocity/acceleration)
- The negative isn't physical, it's pidgin for algebra so late middle high schoolers / early high schoolers can imitate physics without learning any of the above
I'm a bit surprised by your assertiveness. Even if you think I'm being boorish about it (I didn't intend to be, but the downvotes say otherwise), you seem familiar enough with these things to know newton's third law is about vector quantities.
Many different math concepts are used successfully in physics. Even if they may be outside everyday intuition for a layman, that doesn't make them less "real"