Normal force= 24 N
Frictional force acting downwards of 9.6 N in magnitude
Acceleration of the system is 1.2
Normal force acting is given by N=F
As the system is being mobilised upward frictional force will be acting against the direction of effective motion.
Its value will be
Now,let's consider that the system moves upward with acceleration a,so from equation of force we can write,