Domanda 96, Mass and Balance - ATPL - Airline Transport Pilot license

A point near the centre of the aeroplane. It moves longitudinally as masses are added forward and aft of its location.
The point through which the sum of the mass values (of the aeroplane and its contents) is assumed to act vertically.
A variable point, that is dependent on the load distribution for its location, from which all balance arms are measured
A fixed point from which all balance arms are measured. It may be located anywhere on the aeroplane's longitudinal axis or on the extensions to that axis.