Answer-Which of the following statements about the centre of mass (COM) of a system is always true?

The centre of mass COM of a system behaves such that its motion reflects the net effect of all external forces acting on the system. The correct and universally valid statement is that the COM moves as if the entire mass of the system were concentrated at that point and all external forces were applied to it . This principle is foundational in mechanics and applies to all systems, regardless of internal structure or distribution.