Absolutely. There's no penalty for that.
Yes, as long as the player is not considered tackled a defensive player may strip the ball from the ball carrier.
Yes he is.
Snaps the ball to the quarterback and then blocks a defensive player from sacking the quarterback, or blocks to open a hole for a ball carrier.
A defensive player may hold on to a ball carrier's jersey in an attempt to tackle him. However, if a defensive player holds on the the jersey of an offensive player who does not have the ball, that would be a penalty for holding. Likewise, if an offensive player holds on to a defensive player's jersey, that would also be called holding.
Offensive players cannot tackle anyone(they can block or run down the defensive players if they're the ball carrier) unless during the play, there's change of possession(examples: interceptions, fumble recovery), any offensive player can tackle the defensive ball carrier.
Yes
Tackle the ball carrier.
The defensive players. Their positions are the DB's (defensive backs made from corners and safeties), the linebackers et the defensive linemen. But, in fact, everyone can do a tackle to the ball carrier if they are not in possession of the ball.
In college football, once a player's knee touches the ground the play is whistled dead regardless of whether a defensive player made contact with the ball carrier. In the NFL, a defensive player must make contact with the ball carrier to have the play whistled dead. So to answer your question, in college the player is down and the play is over. In the NFL, the player is not down and the play continues.
yes because the player want backwards into the end zone.If the ball has broken the plane when the defensive player makes contact with the ball then its a touchback. If the ball had not broken then plane then the defensive player carried it into the endzone and is a saftey.
Being ahead of the defensive line and the ball, though if a player is ahead of the defensive line but behind the ball, they are not offside
a player that is on the team without the ball. the team that is trying to get back or steal the ball from the offensive team is the defensive team.