formulaThird Law PairThe handbook writes the force on A due to B as equal and opposite to the force on B due to A.F⃗AB=−F⃗BA\vec F_{AB}=-\vec F_{BA}FAB=−FBAVariables & NotationF⃗AB\vec F_{AB}FABforce on A due to BF⃗BA\vec F_{BA}FBAforce on B due to A