A physical pendulum is formed by a two$-$part structure. One part is a thin uniform rod of mass $0\mathrm{.}50$ kg which is free to swing about an axis at one end. The axis of rotation is perpendicular to the plane of the rod's swing. The second part of the structure is a small mass located at the free end of the rod $($further from the axis$),$ which has mass $0\mathrm{.}19$ kg $.$ Treat the small mass as a point mass. The rod$/$mass combination swings with a period of oscillation of $1\mathrm{.}3$ s $.$ What is the length of the rod?

$L=$

m