$10\mathrm{.}7$ Newton's Second Law for Rotation

A $1\mathrm{.}2-$kg disk with a rotational inertia given by $M\frac{R^2}{2}$ is free to rotate on a fixed horizontal axis suspended from the ceiling. A string is wrapped around the disk, and a $0\mathrm{.}80-$ kg mass hangs from the free end of the string. If the string does not slip as the mass falls and the disk rotates, the tension in the string is

$19\mathrm{.}6$ N

$7\mathrm{.}8$ N

$3\mathrm{.}4$ N

$4\mathrm{.}5$ N

$11\mathrm{.}2$ N