# Do action force and reaction force lie on same line?

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fxdung
Do action force and reaction force(Newton's third law) lie on same line?If not then the angular momentum will be violated.I don't know why a cat falling can rotate itself before contact land if the conservative law of angular momentum not be violated?

fxdung
I know that the conservative law of angular momentum is deduced from the symmetry of rotation of space.So the torque of internal force must be zero,then the action and reaction forces must be lie in same axis.But how to prove action and reaction forces lie in same axis(it seem to me sometime the action and reaction forces not lie on same axis)?