The IRB video has players running further apart at higher running speed with a faster ball passing speed and that almost has 2mtre of forward momentum, i would think the speed of the pass in the opposite direction does impact the amount of forward momentum a ball has.
It also shows a ball thrown directly above ones head skywards lacking sideways movement traveled further forward momentum wise than the longer pass at speed.
I'm not digging any deeper hole, it makes no difference to my point of view on how much or how little or how wrong i am understand physics. The point is we have a linesman "on the spot" with the best view in the house and we refuse to give him the benefit of the doubt because we all feel the law of physics should take over in every judgement with a higher chance of getting it right. (without even knowing the ball speed, running speed and distance travelled numbers "on the spot" to justify a decision)
All you are doing is trying to big note yourself because you have an issue with me and working off the joy of "my aim is to dig this fool a hole" like you need some self ego stroking.