> Or it’s a very quick action that it is simultaneous so the output will be the same?
The output Y(s) is the same output that is fed back through H(s) and subtracted from the input (negative feedback loop).
Is the physical feedback instantaneous? Depends on the physical system.
But either way the definition of H(s) will include any delays or other filtering that occur in the feedback loop of the physical system..
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(2B)+(2B)' ?