$11\mathrm{.}144$ Pin A$,$ which is attached to link AB$,$ is constrained to move in the circular slot CD$.$ Knowing that at t$=0$ the pin starts from rest and moves so that its speed increases at a constant rate of $0\mathrm{.}8$ in$/$s$^2,$ determine the magnitude of its total acceleration when $($a$)$ t$=0($b$)$ t$=2$s