8. Centripetal Forces & Gravitation

According to Newton's law of universal gravitation, what happens to the gravitational force between two bodies when the distance between them increases in a two-dimensional space?

Why does $Neptune$ take much longer to revolve around the $Sun$ compared to planets closer to the $Sun$?

Which method is most appropriate for determining the distance to a very far galaxy in the context of gravitational forces in $2^D$?

Why does an object weigh more at sea level by the ocean than it does at the top of a mountain?

Approximately how far is the Moon from the Earth, measured center-to-center?