In a room, there is a tall shelf. On one side of the shelf, Quincy is standing on the floor and looking straight ahead. There is a ball on top of the shelf. On the other side, Rania is hanging upside down from a bar fixed to the ceiling and is also looking straight ahead towards the shelf. What happens to the ball's visibility to Quincy and Rania if the ball rolls off the shelf?

Provide a very brief response.
When the ball rolls off the shelf, Quincy will lose sight of the ball because the shelf will block his view as it falls. However, Rania, who is hanging upside down, will see the ball as it falls off the shelf because her upside-down vantage point gives her a clear line of sight to the top of the shelf where the ball was, and to the space in front of it where the ball will fall.