What is the density $($in g$/$cm$3)$ of $17\mathrm{.}0$ karat gold that is a mixture of $17$ parts gold, $6$ parts silver, and $1$ part copper? $($These values are parts by mass, not volume.$)$ Assume that this is a simple mixture having an average density equal to the weighted densities of its constituents. $($Use $10\mathrm{.}49$ g$/$cm$3$ for the density of silver.$)$

g$/$cm$3$

What is the angular acceleration $($in rad$/$s$2)$ assuming negligible opposing friction? $($Enter the magnitude.$)$

rad$/$s$2$

$($c$)$

What is the angular acceleration $($in rad$/$s$2)$ if there is an opposing frictional force of $20\mathrm{.}6$ N exerted $2\mathrm{.}75$ cm from the axis? $($Enter the magnitude.$)$

rad$/$s$2$