A sphere with a diameter of $7\mathrm{.}20$ cm and a mass of $210$ g is released from rest at the top of a $2\mathrm{.}40$ m$,15\mathrm{.}0$ incline. It rolls without slipping to the bottom. What is the sphere's angular velocity $($in rad$/$s$)$ at the bottom of the ramp? Assume that the local acceleration due to gravity is $-9\mathrm{.}80$ m$/$s$2$ and that the moment of inertia of a sphere is $2/5$ MR$2.$