Answer:
Each half of the force pair acts on a different object.
Explanation:
When a tennis racket strikes a tennis ball a pair force is produced. when the racket strikes the ball the racket exerts an action force on the tennis ball, according to Newton's third law for every action there is an equal and opposite reaction force, as a reaction the ball exert an equal and opposite force on the racket. These forces are often called pair forces.
As the forces acts on different bodies (Action force act on ball and reaction force act on racket) so the net force tennis ball is never zero.
