Answer:
Step-by-step explanation:
You know, I never really thought about this very much. I've always just thought of it as M * V. But when you look at a dictionary definition, it says it is the motion of a body.
That means that speed can be a momentum. Speed is independent of direction. So the colloquial definition does not take into account a change in direction as being very relevant.
The answer then is direction. When physics uses v, it is also counting direction.