A $38\mathrm{.}0$ kg wheel, essentially a thin hoop with radius $1\mathrm{.}36$ m$,$ is rotating at $280$ rev$/$min$.$ It must be brought to a stop in $15\mathrm{.}0$ s$.$

$($a$)$ How much work must be done to stop it$?($Enter the magnitude.$)$

J

$($b$)$ What is the required average power? $($Enter the magnitude.$)$

W