In the above question disc B is brought in contact with disc A, they acquire a common angular velocity in time t. The average frictional torque on one disc by the other during this periodis:

In the above question disc B is brought in contact with disc A, they a

1.	In the above question disc B is brought in contact with disc A, they acquire a common angular velocity in time t. The average frictional torque on one disc by the other during this periodis:
Answer» `(2I omega)/(3t)` `(9I omega)/(2T)` `(9I omega)/(4t)` `(3I omega)/(2t)` Solution :Let `omega_(1)` is the COMMON angular velocity acquired by both the discs then using conservation of angular momentum we can WRITE the following: `I(2omega)+(2I)omega=(I+2I)omega_(1)impliesomega_(1)=(4OMEGA)/(3)"".....(i)` Initial angular momentum of A: `L_(1)=I(2omega)=2Iomega` Final angular momentum of A: `L_(2)=I(4omega//3)` Angular impulse = Change in angular momentum `taut=\|L_(2)-L_(1)\|impliestaut=(2Iomega)/(3)impliestau=(2Iomega)/(3t)` OPTION (a) is correct.