$5/121$ For the instant represented, corner $\backslash ($ C $\backslash )$ of the rectangular plate has an acceleration of $\backslash (5\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}^\{2\}\backslash )$ in the negative $\backslash ($ y $\backslash )-$direction, and the plate has a clockwise angular velocity of $\backslash (4\backslash$mathrm$\{$rad$\}/\backslash$mathrm$\{$s$\}\backslash )$ which is decreasing by $\backslash (12\backslash$mathrm$\{$rad$\}/\backslash$mathrm$\{$s$\}\backslash )$ each second. Determine the magnitude of the acceleration of $\backslash ($ A $\backslash )$ at this instant. Solve by scalar$-$geometric and by vector$-$algebraic methods.

Please solve in both scalar and vector form.

Problem $5/121$