Kinematics in rhombi

A hinged structure consists of rhombi with side lengths $l$ , $2l$ $3l$ (see the figure). Point $\text{A}_3$ is moving at a constant velocity $\text{v}_0$ . Find the velocity and acceleration of point $\text{B}_2$ when all angles of the structure are equal to $90^{\circ}$ .

The velocity and acceleration of $\text{B}_2$ can be expressed as $\dfrac{v_0 \sqrt a}b$ and $\dfrac{v_0 ^2 \sqrt c}{dl }$ , respectively, where $v_0$ and $l$ are the values as mentioned above, with $a,b,c,d$ are all positive integers, and both $a$ and $c$ are square-free.

Submit your answer as $a+b+c+d$ .