A pulley of radius 2 m is rotated about its axis by a force $\mathrm{F} = \left(20\mathrm{t} - 5\mathrm{t}^{2}\right)$ Newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is $10\,\mathrm{kg\,m}^2$, the number of rotations made by the pulley before its direction of motion is reversed, is:\\
(1) more than 3 but less than 6\\
(2) more than 6 but less than 9\\
(3) more than 9\\
(4) less than 3