Log1989 problem №2.27

The mass of the ball 1 is 1.5 times smaller than the mass of the rod 2, whose length is L = 1 m. The masses of the block and the filament, as well as the friction in the axis, are negligibly small. The ball was set at the same level with the lower end of the rod and released. Find the time interval after which the ball is leveled with the upper end of the rod.