A particle of mass 'm' is rigidly attached at 'A' to a ring of mass '3m' and radius 'r' as shown. The system is released from rest and rolls without sliding. The angular acceleration of ring just after release is:
I am getting different angular accelerations of the ring using point P (Instantaneous Axis of Rotation) and Centre of Mass. When solving about point P the only torque acting is mgr by the particle. When solving about centre of mass torque by friction and particle is acting on the system.
I am aware that this seems like a 'do my homework question' but I do not want anyone to solve the question for me. I just want to know if there is something wrong about my understanding of Rolling motion.