The uniform 16.1-lb slender bar is hinged about a horizontal axis through O and released from rest

Question:

The uniform 16.1-lb slender bar is hinged about a horizontal axis through O and released from rest in the horizontal position. Determine the distance b from the mass center to O which will result in an initial angular acceleration of 16.1 rad/sec², and find the force R on the bar at O just after release.