\[\boxed{\mathbf{1548}\mathbf{.}}\]
\[\mathbf{Угол\ поворота\ колеса}\mathbf{:}\]
\[\varphi(t) = kt^{3};\]
\[k - коэффициент.\]
\[За\ 2\ с:\]
\[\varphi(2) = k(2)^{3} = 2\pi\]
\[8k = 2\pi\]
\[4k = \pi\]
\[k = \frac{\pi}{4}.\]
\[\varphi(t) = \frac{\pi}{4}t^{3};\]
\[\varphi^{'}(t) = \frac{\pi}{4}\left( t^{3} \right)^{'} = \frac{3\pi}{4}t^{2}.\]
\[Через\ 4\ секунды:\]
\[\varphi^{'}(4) = \frac{3\pi}{4} \bullet 4^{2} = 3\pi \bullet 4 =\]
\[= 12\pi\ \left( рад\text{/}с \right).\]
\[Ответ:\ \ 12\pi\ рад\text{/}с.\]