The capability of the join force is described as the magnitude of influence that the joint force can do after combining all of their resources and experience. Usually this capability will be far greater compared to if they are stand alone as their own unit.
For example.
The Navy has deep expertise in operating within water terrain.
The Air force has the expertise in operating within the sky terrain.
When the Air Force joining the navy in a certain operation, the navy now has more ways to win against the enemies since they can leverage on air attacks provided from the Air force.
