Question $5$

"The $2-$m$-$long bar is confined to move in the horizontal and vertical slots A and B$.$ If the velocity of the slider block at A is $6$ m$/$s $($move to the right$),$ determine the magnitude of block B$\text{'}$s downward velocity $($in m$/$s$)$ at the instant with angle theta $=30$ degree. Express your answer with positive number since we know already that it's moving downward"

Graph for Problem $5$: