Answer:
2.4 rad/s
Step-by-step explanation:
= Initial angular velocity = 3.2 rad/s
= Final angular velocity of the system
= Initial angular momentum = 1.8 kgm²
= Final angular momentum = 0.6 kgm²
As there is no external torque then the angular momentum in the system is conserved

The angular velocity of the system is 2.4 rad/s