Homework H$\mathrm{.}4.$E

Given: Blocks A and B $($having masses of $m$ and $2m,$ respectively$)$ are constrained to move along the smooth surfaces shown in the figure below. Member $AB,$ in the shape of a quarter$-$circle arc, connects blocks A and $B,$ with $AB$ having a mass that is negligible compared to the masses of A and $B.$ At the position shown, when the center $O$ of the circular arcAB is directly below block $B,$ the system is released from rest.

Find: For this position, determine the acceleration of blocks A and B on release.

HINT: Note that $AB$ is a two$-$force member. What does this say about the direction of the reaction forces on blocks A and B due to member AB $?$