Questions pertaining to Blender's built-in rigid body physics simulator and rigid body simulations in the Blender game engine. Rigid body physics are used to accurately calculate dynamic motion of non-deforming objects.
The rigid body simulation can be used to simulate the motion of solid objects. It affects the position and orientation of objects and does not deform them.
Unlike the other simulations in Blender, the rigid body simulation works closer with the animation system. This means that rigid bodies can be used like regular objects and be part of parent-child relationships, animation constraints and drivers.
Viewport Rigid Body Simulation documentation at the Blender Manual
Game engine documentation also at the Blender Manual The BGE was removed from Blender in version 2.8