\[s(t) = 6t^{2} - t^{3}.\]
\[1)\ v(t) = 6 \bullet 2t - 3t^{2} = 12t - 3t^{2}.\]
\[2)\ 12t - 3t^{2} \geq 0\]
\[3t\left( 4 - t^{2} \right) \geq 0\]
\[(t + 2)t(t - 2) \leq 0\]
\[t \leq - 2;\ \ \ 0 \leq t \leq 2.\]
\[3)\ Точка\ максимума:\]
\[t = 2;\]
\[v(t) = 24 - 12 = 12.\]
\[Ответ:\ \ 12.\]