Tangential or normal acceleration?

[EvoN1020v]

Hello guys I'm a bit stumped here - why is [math]a_B[/math] tangential to the right along the x-axis as seen on bottom of the attached photo. I understand that velocity is zero at point B but why is acceleration tangential along x-axis instead of normal? If the bar is falling downward at center G then it has a path about B right? So B should have normal acceleration to the right instead of tangential. Maybe someone can explain that better for me. A bit frustrated here and thanks in advance.