Objects at rest – how are they regarded in terms of “carrying out”?
For example, a thrown object. We have learned (Shabbat 7a-b) that if an object is thrown between a private and a public area, if it travels less than 4 cubits or over 10 cubits high, the thrower is not liable.
But what if it lands on a sloped area which is within 4 cubits distance and then it rolls beyond the limit? The Mishnah states:
IF ONE THROWS[ [AN OBJECT] WITHIN FOUR CUBITS BUT IT ROLLS BEYOND FOUR CUBITS, HE IS NOT CULPABLE;
BEYOND FOUR CUBITS BUT IT ROLLS WITHIN FOUR CUBITS, (by the wind, for example) HE IS CULPABLE
But Rabbi Johanan says: “Providing it rests [beyond four cubits] on something”
The object at rest is its definition of distance.
However, Rab Judah said in Rab’s name regarding a very steep slope: “If a [sloping] mound attains [a height of] ten [handbreadths] within [a distance of] four, and one throws [an object] and it alights on top of it, he is culpable”
Gravity, it seems, is inevitable. The wind is not.
Objects on top of other objects are also interesting. For example, a nut landing on water is “not at rest” (natural state). Here is where it is interesting:
Raba propounded: If a nut [lies] in a vessel, and the vessel floats on water, what [is the law]? Do we regard the nut, and behold it is at rest; or do we regard the vessel, and behold it is not at rest?
The question is not answered – but it is a classic question of Relativity! The reality depends on perspective.
Einstein’s Physics in Talmud? Not exactly. But fun to read with modern eyes. That is also relative!