A small bead is placed on a thin circular loop of radius \(25\,\text{cm}\) which is rotating about its vertical diameter with a constant velocity of \(10\,\text{rad s}^{-1}\). The angle made by the radius vector joining the center of the loop to the bead with the vertically downward direction is (Neglect friction and take \(g=10\,\text{m s}^{-2}\)):