Forces acting on mass m and mass ( n × m ) after releasing the system is shown in figure.
Heavy mass will move downwards and lighter mass mass move upwards. Magnitude of acceleration a is same for both masses
Magnitude of acceleration a = ( Net force ) / ( Total mass )
Let us consider the coordinate system as shown in figure
acceleration of centre of mass acm is given as
Above acceleration of centre of mass is calculated with respect to origin of coordinated system considered.
Origin of coordinate system is centre of pulley .