A circular platform is mounted on a frictionless vertical axle. Its radius and its moment of inertia about the axle is
. It's initally at rest. A
man stands on the edge of the plate form and begins to walk along the edge at the speed of
relative to the ground. Time taken by the man to complete one revolution is -
According to the conservation of momentum -
..............(1)
put the given all values-
Now,
Hence option 3 is correct.