A uniformly charged insulating rod of length $17\mathrm{.}0$ cm is bent into the shape of a semicircle as shown in the figure below. The rod has a total charge of $-6\mathrm{.}50$C$.$ Find the electric potential at O$,$ the center of the semicircle.

MV

A semicircular rod has point O at its center. Point O is to the right of the semicircle, midway between its endpoints.