It is where the ball is at time of contact by player. If the fielder contacts ball while he is in fair territory but the ball is in foul territory, it is a foul ball. In your case, if the ball passed the bag fair and player knocked it foul, it is a fair ball.
OK, maybe I shouldn't have said anything about the dems. But Yobama happens to be one, and he is doing his dead level best to turn this great nation into a socialist one.
The election can't get here quick enough to get this incompetent clown out of office. Just hope enough of us get out and vote to keep the dems from putting another in his place, because they all feel that Yobama is the best thing since sliced bread.