Paragraph: P_ 17 - 19 : Paragraph for Questions Nos. 17 to 19 Two...

Paragraph: $\mathbf{P}_{17 \text{ - } 19}$ : Paragraph for Questions Nos. 17 to 19 Two discs A$and$B$are mounted coaxially on a vertical axle. The discs have moments of inertia I and 2I, respectively about the common axis. Disc A$ is imparted an initial angular velocity $2 \omega$ using the entire potential energy of a spring compressed by a distance $x_1$. Disc $B$ is imparted an angular velocity $\omega$ by a spring having the same spring constant and compressed by a distance $x_2$. Both the discs rotate in the clockwise direction.Question: When disc $B$ is brought in contact with disc A$, they acquire a common angular velocity in time$t$. The average frictional torque on one disc by the other during this period is$