A thin uniform rod $($length L $=0\mathrm{.}72$ m$,$ mass m $=1\mathrm{.}16$ kg$)$ is free to pivot about a horizontal frictionless pin through one of its ends. The rod is released when it is $60.$ below horizontal.

$($a$)$ Calculate the angular acceleration of the rod at the instant it is released. $(6$ pts$)$

$($b$)$ From the point of release to its lowest point, the center of mass of the rod descends through the vertical distance h$=0\mathrm{.}048$ m$.$ Calculate the speed of the low end of the rod when it reaches its lowest point. $(4$ pts$)$