The 24-lb disk is rigidly attached to the 7-lb bar OA, which is pivoted freely about a

Question:

The 24-lb disk is rigidly attached to the 7-lb bar OA, which is pivoted freely about a horizontal axis through point O. If the system is released from rest in the position shown, determine the angular velocity of the bar and the magnitude of the pin reaction at O after the bar has rotated 90°.