Two objects that may be considered point masses are initially separated by a distance d. the separation distance is then decreased to d/4. how does the gravitational force between these two objects change as a result of the decrease?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)