The four-bar linkage of Prob. $5 / 86$ is repeated here. If the angular velocity and angular acceleration of drive link $O A$ are $10 \mathrm{rad} / \mathrm{s}$ and $5 \mathrm{rad} / \mathrm{s}^{2},$ respectively, both counterclockwise, determine the angular accelerations of bars $A B$ and $B C$ for the instant represented.