A steady two-dimensional flow field is specified by the stream function $$\psi = kx^{3}y,$$ where $x$ and $y$ are in meter and the constant $k = 1 \:m^{-2}\:s^{-1}$. The magnitude of acceleration at a point $(x, y) = (1\;m, 1\;m)$ is _______________ $m/s^{2}$ (round off to $2$ decimal places).