A man stands on a rotating platform, with his arms stretched horizontal
Channel: Doubtnut
Date: 02/08/2020

A man stands on a rotating platform, with his arms stretched horizontal holding a `5 kg` weight in each hand. The angular speed of the platform is `30` revolutions per minute. The man then brings his arms close to his body with the distance of each weight from the axis changing from `90 cm` to `20 cm`. moment of inertia of the man together with the platform may be taken to be constant and equal t `7.6 kg m^(2)`. (a) What is the his new angular speed ? (Neglect friction.)  (b) Is kinetic energy conserved in the process ? If not, from where does the change come about ?