You really can't tell. You don't know if its speed was constant for the whole second, or whether it was accelerated, decelerated, intermittent, bouncing back and forth, etc. All you know is that after 1 second, it had moved 16 ft.
IF its speed was constant AND it moved in a straight line, THEN it moved 4 ft in the first quarter of that second.
If it rolled off of a roof and FELL 16 ft in the first second, then it fell 1 foot in the first quarter second.
