A uniform disk of radius $0\mathrm{.}549m$ and unknown mass is constrained to rotate about a perpendicular axis through its center. A

ring with the same mass as the disk is attached around the disk's rim. A tangential force of $0\mathrm{.}201N$ applied at the rim causes an

angular acceleration of $0\mathrm{.}113ra\frac{d}{s^2}.$

Determine the mass $m$ of the disk.

$m=,kg$