14. Three masses of 1 kg, 6 kg and 3 kg are connected to each other by threads and are placed on table as shown in figure. What is the acceleration with which the system is moving ? Take g = 10 m s–2:

If you are talking about the system then consider all the three masses within a one mass system
.i.e tension force being internal forces hence it will not have any use.
thus system acceleration becomes:

a = F/(1 + 6 + 3) = F / 10 m/s^2.
common accelrn. fr all masses.
siince yr. figure is missing

First draw the free body diagram of all the three masses. Then applying the Newton's second law of motion we get three equations 3g-T2=3a, T1-10=a, T2-T1=6a. solving these equations will give you a=2m/s