From the article:
"engineers mistook acceleration readings measured in English units of pound-seconds for a metric measure of force called newton-seconds."<p>Yikes. Acceleration is change in velocity per unit time, and would be measured in feet/second^2 or meters/second^2.
Both pound seconds and newton seconds are measures of momentum (mass times velocity). He then goes on to define a custom domain called "acceleration" but gives it units of "1 m*kg/s".<p>Seems to know his stuff when it comes to PostgreSQL, but evidently it's been too long since he took a high school physics class.