What is the sum of the forces in an action reaction pair?
o a.
always less than zero
b.
always greater than zero
c.
always equal to zero
sometimes less than zero
reset

C.  always equal to zero

Explanation:

According to newton's third law of motion, every action is always associated with equal and opposite reactions.

If object A applies a force to object B, then object B imparts a force equal to that of A towards it. So, the direction of force is opposite to each other.

The action force is called 'Fa' and the reaction force is '-Fr'

Due to the reversal of direction, the magnitude of the reaction force has a negative sign.

                                           Fa = - Fr

∴                                          Fa  +  (-Fr) = 0

Hence, sum of these two forces is equal to zero.