The original article was titled “Five Seconds Can Be a Lifetime” (or something close to that) and was in the Football Outsiders book for that year. Since I remember Chris Johnson being in the draft class discussed in that article, I believe it is Pro Football Prospectus 2008.

I have the book, but my books are all packed up and I have no clue where any one is.

Yeah, I ran down what I assume is the original Washington Post article in which he talks about correlation coefficients with ‘carries’ and DYAR, but doesn’t discuss methodology (neither statistics nor physics).

N.B.: I had it wrong above – it should be mass / (time^x).