I know this is not the real sense of the thread, but it bothers me that students
think/speak of a position-time graph as a distance-time graph. The difference in the
words "position" and "distance" seem important to me, and the mixing of the words
misleading to the students. My guess is that the words "change of distance" are _not_
used when finding the slope, and I suspect that folks mean "distance from an origin" to
be understood from the shorthand "distance" (meaning position.) If this supposition is
correct about shorthand meaning, how does one distinguish vector displacement from
scalar distance? It seems like the sort of discipline (or lack of) that gets us into
trouble with misconceptions and misapplication of concepts. Perhaps this is just
nit-picky semantics.