At t 2, the angular velocity is zero, with a non-zero (positive) angular acceleration. At that time, the direction of rotation for BC is changing from CW to CCW. In summary, you should never assume ...

The angular momentum principle says that the net torque (about the center) is equal to the moment of inertia times the angular acceleration of the disk (about the center).

Participants performed touchscreen-based reaching tasks while wearing wireless motion sensors, which recorded linear acceleration, angular velocity, and roll-pitch-yaw orientation at millisecond ...