When a player throws a baseball while standing still, they do not move backward due to the conservation of momentum, which states that the total momentum of a closed system remains constant unless acted upon by an external force. The forces involved during the throw are internal to the player-ball system, meaning they do not result in any net movement. If the player were on ice, the lack of friction would allow them to slide backward, illustrating the principle of momentum conservation more clearly. The normal force from the ground counteracts the player's force, preventing backward movement in normal conditions. Thus, the player's mass relative to the ball's mass also plays a crucial role in the outcome of the throw.
