P$3\mathrm{.}23$ The board is hanging by two ropes and swings so that, at a given instant, it is horizontal, with vertex A moving at a velocity $v^A=v{n}_2,$ vertex B at a velocity $v^B=v(-3n_1+n_2),$ and the vertical component of the velocity of vertex C being $v,$ where the basis $n_1,n_2,n_3,$ fixed in the board, has the indicated directions and $v$ is constant. Find the angular velocity and acceleration of the board at that instant.

$3\mathrm{.}23$: $\frac{v}{2a}(2n_2+n_3)$;$0.$