Newton's third law explains that every action creates a force that is met by an equal reaction force from the opposite direction. When two objects interact, they exert a force on each other. The action force of a spiked ball meets the reaction force of a player's block. A team scores a point when the action force of a spiked ball meets the reaction force of the opposing team's court. The hard floor has more force than the soft ball, so the ball bounces off the court to equalize the reaction of the impact.
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