The $100-\mathrm{kg}$ spool is resting on the inclined surface for which the coefficient of kinetic friction is $\mu_{k}=0.1 .$ Determine the angular velocity of the spool when $t=4 \mathrm{~s}$ after it is released from rest. The radius of gyration about the mass center is $k_{G}=0.25 \mathrm{~m}$.