A sphere with mass \(m\) is abandoned (initial velocity is 0) from point \(A\), sliding along \(ABCDEF\).
\(BCDE\) is a circle with radius \(R\).
The acceleration of gravity is equal to \(g\).
The intensity of the force that the ball exerts on the surface at point \(D\) is \(mg\).
Calculate the absolute value of the angular velocity of the ball at point \(D\).