Problem $16\mathrm{.}157-$ Centroidal rotation

NOTE: This is a multi$-$part question. Once an answer is submitted, you will be unable to return to this part.

The uniform rod $AB$ of weight $W$ is released from rest when $=73.$

Problem $16\mathrm{.}157.$b $-$ Centroidal rotation

Assuming that the friction force between end A and the surface is large enough to prevent sliding, defermine the normal reaction at A immediately after release.

The normal reaction at $A$ is

$($x$)$ mguarr.