Problem 1.364

The rod $A B$ oriented parallel to the $x^{\prime}$ axis of the reference frame $K^{\prime}$ moves in this frame with a velocity $v^{\prime}$ along its $y^{\prime}$ axis. In its turn, the frame $K^{\prime}$ moves with a velocity $V$ relative to the frame $K$ as shown in Fig. $1.94 .$ Find the angle $\theta$ between the rod and the $x$ axis in the frame $K$.