1. The problem statement, all variables and given/known data Two equal, parallel and opposite forces at at both sides of a horizontal disk that lies on a smooth table, according to the picture. The mass is m and the moment of inertia is: kmR2 Angular momentum round the center point A: [tex]2FR=kmR^2 \cdot \alpha[/tex]. Angular momentum round the point B on the outer edge: [tex]2FR=mR^2(k+1) \cdot \alpha[/tex]. It is clear i will get 2 different angular acceleration [itex]\alpha[/itex], how come? 2. Relevant equations M=I[itex]\alpha[/itex] Shteiner's theorem of the parallel axis: Ib=Ic+mb2 3. The attempt at a solution It is clear that the second equation is wrong, since the first one is right, since it is round a static point. Maybe i have to compensate, when calculating round point B, for it's acceleration? How? maybe with D'alamber's sentence? But then, can i solve only from the point of view of the accelerating system? I want to solve from the static, inertial system.