A question similar to this was in irodov.
I've substituted v from the second imagr.
I believe the concept is this only, I may have done something wrong in the calculation or something else.
Basically, imagine the 2m mass on the top, while hoop goes with velocity v.... Get the max v possible for hoop to stay on the ground. Then apply conservation of energy to get velocity when 2m is at its lowest(just like the students who gave jee 2018 )