what does action force mean??

Question

PLEASE
i can't find it anywhere!

Answer 1

All right, I'll help you. This strange term, not generally used in the physics community, comes from the way Newton's 3rd law is written. In latin, he meant to say, "For every action there is an equal and opposite reaction". However, the term "action" had later come to mean something different in physics, having the physical dimensions of energy x time, or distance x momentum, which are not the physical dimensions of force. Newton's 3rd law today really should read, "For every force there is an equal and opposite force". But for the sake of perserving his use of the word, and to keep the generality of the law, some later writers put down, "For every action FORCE there is an equal and opposite REACTION force."

My suggestion to you is to just drop the term "action force" altogether, because it has little value in today's nomenclature in physics. We have force, and we have action, and they are not the same thing. You won't find "action force" used anywhere else in physics.