in or out of bounds

[MRD]

Fed. football. Please give your opinion on the following scenerios: Running back sweeping the end. When tackled his knee hits in bounds and the ball hits the sideline chalk at the same time...in or out? Scenerio #2: running back sweeps the end. When he is tackled his knee hits in bounds and the ball is breaking the plane of the sideline chalk but is not touching the ground. in or out? Scenerio #3; running back sweeping the end. When he is tackled the ball and his whole lower body are in bounds but his head lands on the sideline chalk. in or out? I contacted the State fed office re: this and , to be honest, ithe rules guy wasn't sure. Thanks for your help