if the body describes a vertical circle then the minimum velocity at angle theta from lowest position is

Answer 1

If it is to make it around the circle then the velocity at the top must be positive. (1/2)m v^2 >/= m g (2R) if it is running around a track and can fall, then the centripetal acceleration at the top must be 1 g at least. mv^2/R >/= m g You do not say which.