A block of mass $$m = 1$$ kg slides with velocity $$v = 6$$ m s$$^{-1}$$ on a frictionless horizontal surface and collides with a uniform vertical rod and sticks to it as shown. The rod is pivoted about O and swings as a result of the collision making angle $$\theta$$ before momentarily coming to rest. If the rod has mass $$M = 2$$ kg, and length $$\ell = 1$$ m, the value of $$\theta$$ is approximately (take $$g = 10$$ m s$$^{-2}$$)