I need help with figuring out how to come up with the posted answer please.

Crank OA with a length of $0\mathrm{.}16$ m is rotating about O with an angular velocity of

$\backslash$omega $=2$ra$($d$)/($s$)$ and angular acceleration $\backslash$alpha $=2$ra$($d$)/($s$^(2)).$ Crank OA has a counter$-$

clockwise angle, $\backslash$phi $=3$ measured from the vertical$-$down position and rodAB,

with length $0\mathrm{.}79$ m $,$ is at an angle $\backslash$theta $=0\mathrm{.}3$rad from the horizontal ground.

Determine the acceleration of point B$.$