A uniform disc of mass `M` and radius `R` is pivoted about a horizontal axis passing through its edge. It is released from rest with its centre of mass at the same height as the pivot.
A. The angular velocity of disc when its centre of mass is directly below the pivot is `sqrt((4g)/(3r))`
B. The force exerted by the pivot at this instant is `7/3mg`
C. Angular momentum of disc is conserved
D. Angular acceleration of disc at the given instant is zero
