In a world where gravity inexplicably reverses its direction every five minutes, Sunita and Hideki are playing catch in an open field. Sunita tosses the ball to Hideki just as gravity reverses, sending everything not anchored to the ground hurtling towards the sky. Both Sunita and Hideki jump at the right moment to catch hold of a large, sturdy tree. As they cling to the branches, Sunita, who is directly above Hideki, is worried the ball might hit him on its way up. Should Hideki be concerned about the flying ball?
Respond very briefly.
Hideki does not need to be concerned about the ball hitting him due to gravity's reversal. When Sunita threw the ball towards Hideki, it was under the influence of normal gravity. Right after the throw, the reversal of gravity would cause the ball to change its direction and accelerate upwards, away from Hideki. Since Sunita is directly above Hideki, and they are both holding onto the same tree, the ball's upward trajectory will not intersect with Hideki's position. Instead, it will continue ascending along the path it was on when gravity reversed, which would be somewhere between Sunita and Hideki, but not on Hideki.