Answer:
Angular acceleration will be
Step-by-step explanation:
We have given initial angular speed of a particular disk
![\omega _i=646.1rad/sec](https://img.qammunity.org/2020/formulas/physics/high-school/rojitk2gtvmztr8kvy1jwc5wcacs2xvuwi.png)
And it finally comes to rest so final angular speed
![\omega _f=0rad/sec](https://img.qammunity.org/2020/formulas/physics/high-school/2rjvjb9v6rbrikaacn9ztntmdxp5zg48qc.png)
Time is given as t = 0.569 sec
From third equation of motion we know that
![\omega _f=\omega _i+\alpha t](https://img.qammunity.org/2020/formulas/physics/college/3mp2fa1m0qvbmtbx4scyhvo8302jz722ks.png)
So angular acceleration
![\alpha =(\omega _f-\omega _i)/(t)=(0-646.1)/(0.569)=1135.5rad/sec^2](https://img.qammunity.org/2020/formulas/physics/high-school/xkpo9yeiuf022k8akq9umtx932owpxe354.png)