In this sub-menu, the following commands allow you to work with Physics:
Allows you to toggle the physical state of an object (Green = physics on, Red = physics off).
Enable/disable gravity. All objects that have their physical state toggled on will be subject to gravity.
Enable/disable physics. This is the main switch to use physics. Once toggled, all objects that have their physical state toggled on will be subject to physics (and if it is toggled on: gravity).
To better understand how you can use Physics in SkyReal, please refer to the detailed Physics command page.