Gravity is an in-game mechanic obeyed by entities. It makes entities fall if there is no Block directly below them until they hit a block or fall into The Void. All Mobs obey gravity, except for Ghasts, Bats, and sometimes Blazes.
Gravity in Minecraft is not the same for all entities. Each group of entities undergoes a different amount of acceleration due to Gravity. There is also a drag force which is proportionate to velocity, again dependant on the type of entity.
Blocks Obeying Gravity
|Kind||Acceleration due to Gravity (m/s²)|
|Players and Mobs||32|
|Items, Top Snow, Sand, Red Sand, Gravel, TNT, Anvils||16|