By my logic, there should be some time lag between the action and the reaction, however small the lag.So can we say that an effect to a reaction happens instantaneously in our universe?
1 Answers
there should be some time lag between the action and the reaction
Although action and reaction labels are often used in the context of Newton’s 3rd law, the fact is that the mathematics does not distinguish in any way between the two. There is no physical distinction between action and reaction forces.
Instead, you should simply think of forces as coming in pairs according to the third law. The two forces are equal and opposite sides of the same interaction between two systems, but there is no action and reaction designation.
Furthermore, the two forces in a 3rd law pair must always be simultaneous. If it were not so then momentum would not be conserved as the momentum of one system would change while the momentum of the other system would not change for some brief duration.

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