The Physics area shows the following statistics about the physics in the scene:-
Active Rigidbodies is the number of rigidbodies that are not currently sleeping (ie, they are moving or just coming to rest).
Sleeping Rigidbodies is the number of rigidbodies that are completely at rest and therefore don’t need to be updated actively by the physics engine (see Rigidbody Sleeping for further details).
Number of Contacts is the total number of points of contact between all colliders in the scene.
Static Colliders is the number of colliders attached to non-rigidbody objects (ie, objects which never move under physics).
Dynamic Colliders is the number of colliders attached to rigidbody objects (ie, objects which do move under physics).