Two disks of the same thickness and same material are attached to a shaft as shown. The 3-kg disk A has a radius rA = 100 mm, and disk B has a radius rB = 125 mm. Knowing that the angular velocity of the system is to be increased from 200 rpm to 800 rpm during a 3-s interval, determine the magnitude of the couple M that must be applied to disk A.
![606_1e3e1c4b-24bf-42b4-8f5a-fe884e8033c2.png](https://secure.tutorsglobe.com/CMSImages/606_1e3e1c4b-24bf-42b4-8f5a-fe884e8033c2.png)