Problem 1.259

In the arrangement shown in Fig. 1.65 a weight $A$ possesses mass $m$. a pulley $B$ possesses mass $M$. Also known are the moment of inertia $I$ of the pulley relative to its axis and the radii of the pulley $R$ and $2 R .$ The mass of the threads is negligible. Find the acceleration of the weight $A$ after the system is set free.