Originally Posted by bombmk
I actually think its too scientific a term to use in the rules - phrased like that at least. It might be moving due to being thrown - but the 550 _meter_ roller is not in any way rolling due to the momentum the thrower put in it. If you throw disc up into the wind, any momentum you put on it is gone the moment it starts falling backwards. It is no longer moving due to the momentum that you put on it.
If I throw you a tennisball and you throw it up in the air and hit it with a racket, is it still flying through the air due to the momentum I put on it?
"A disc is at rest once it is no longer moving by its own momentum."
That should cover stopping on moving branches or water as well.
Not sure its bulletproof, so fire away.
It's purely semantics. Maybe momentum isn't the right word to use from a scientific standpoint. In a scientific sense, momentum is simply a measure of movement. It has no source, it's just mass*velocity. With the multitude of forces at play in the flight of a flying disc, it's impossible to quantify the specific cause of movement.
However, from a layman's perspective, it's the best word to use to convey the intent of the rule.
The intent is to say that the disc is at rest when it stops moving. However, for cases where it lands in water or a tree swaying in the wind, it's motion may never completely stop. So in those cases, it is at rest when it's movement is caused only by the motion of the water or tree.