A smooth uniform vertical hoop of radius r and mass M kg stands in a vertical plane on a horizontal surface.
The hoop threads two small rings,each of mass m kg. The rings are released from rest at the top of the hoop.
when the two rings have each fallen through an angle of 6 on opposite sides of the hoop, show that the normal force of reaction exerted by the hoop on each ring is
where this force is taken to act in the outward direction from the centre of the hoop
show that the hoop will rise from the table if