The sum of the forces in the pair of action and reaction forces are always equal to zero.
Answer : Option C
Step-by-step explanation:
The action force when applied to the surface or body, in contact, produces a reaction force. This reaction force is produced in an strength or force equal to that of the action force applied as a pure form of reaction and is opposite to the direction of the action force applied.
Hence the action force and reaction force are opposite in their application and so by the convention, the action force gets positive force and reaction force gets negative force.
Sum of action reaction force pair = action force - reaction force = 0.