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Re: [Phys-L] feeler-dealer, third law, et cetera



If we adopt that approach, it means force is not a vector.
I say that because according to the definition of vector, the sum of two vectors must be *A* vector.

In that sense, can't we say that the "single vector force" of 15 N Left = (20 N Left + 5 N right), has an "equal and opposite single vector force" consisting of (20 N right + 5 N left)? After all, we can do the vector addition just as well on the two "reaction forces" as on the two "action forces".

Or put another way ...
* if we are focusing on the force Mr. A applies on the left side of the Crate only, then there is a N3 counterpart of the Crate pushing back on Mr. A.
* if we are focusing on the force Ms. B applies on the right side of the Crate only, then there is a N3 counterpart of the Crate pushing back on Ms. B.
* if we are focusing on the NET force Mr. A & Ms. B apply the Crate only, then there is a N3 counterpart of the Crate pushing back on Mr. A & Ms. B.

F_AC = - F_CA.
F_BC = - F_CB.
F_(A&B)C = - F_C(A&B).

Or we could have F_(universe)C = - F_C(universe)

It seems the notation still works perfectly fine here.