In this link about finding equations of motion of cart pole problem, There is an equation about acceleration of center of mass of the pole. Screenshots of them below.
I don't understand why they have more than two parts about angular acceleration - $\varepsilon \times r_p$ and $\omega \times (\omega \times r_p)$?
If I'm being right, first one is torque, and second one is acceleration of a point in circular movement.
I guess in some part I'm being incorrect, but I don't understand why they put two angular acceleration of it? It's copy of them, aren't they?