You would have obstruction on the player that interfered with the runner, the play however is not dead. The fielder could be ejected for unnecessary excessive contact. The runner will be awarded the base he was going to but anything after that base is runner discretion meaning if the runner advances to any other base it is at their own risk.
If the fielder is attempting to make a play on a batted ball, and the base runner runs into the fielder, then the runner is out. If there is no play to be made on the ball, and the fielder is standing in the base line and is run into by the base runner, then it is interference on the fielder, and the runner is awarded the next base.
No, the fielder does NOT have to touch the base before tagging a runner out. The fielder only touches the base on a forced play.
The runner would be out if he does not return to the base before the fielder throws it to the base. Runners may advance from their base as soon as the ball is touched by a fielder. In this case, the runner would not be out.
Yes. The fielder covering the base does NOT have to tag the runner. The runner is forced out when the fielder steps on the base before the runner can make it back. Got that.
Yes, if the fielder had full possession of the ball when he touched the base the runner is out.
The runner is out as long as the fielder you touches has the ball in his glove
the fielder must tag the base runner
Not always. They can be forced out if there is a runner behind them and the fielder tags the base they were running to.
A fielder's choice is when a fielder has choosen to make an out on another runner on base when he could of gotten the batter/runner out instead. The batter/runner is safe, therefore reaching base via a fielder's choice. Please note that this counts as an at-bat and goes against the batter's batting average.
He does if he can get back and touch it in time before a fielder does. If the runner makes no attempt to return to the base and a fielder touches it and appeals, the runner is out.