A solid disc of radius 20 cm and mass 10 kg is rotating with an angular velocity of 600 rpm, about an axis normal to its circular plane and passing…

A solid disc of radius $\displaystyle 20$ cm and mass $\displaystyle 10$ kg is rotating with an angular velocity of $\displaystyle 600$ rpm, about an axis normal to its circular plane and passing through its centre of mass. The retarding torque required to bring the disc at rest in $\displaystyle 10$ s is \_\_\_\_ $\displaystyle \pi \times 10^{-1} \mathrm{Nm}$.