Weight is not a primary factor in determining position (though a 140 pounder would probably be an exceptionally poor choice for offensive linesman, unless this is in some kind of middle school program).
140lbs is 63.5kg
outside linebacker
Fullback
the football position ks is Kicker
That would be the Outside Line Backer on the Defensive Team.
Which American Football position would suit me best i weigh 175lbs
63.5kg
i think wide reciever
Play fullback
Cheerleader.
In football, I would say a wide receiver.
140lbs