A man stands on a rotating platform, with his arms stretched horizontally holding a 5 kg weight in each hand

rotational-particles
cbse

#1

A man stands on a rotating platform, with his arms stretched horizontally 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. The moment of inertia of the man together with the platform may be taken to be constant and equal to 7.6 kg${{m}^{2}}$. What is his new angular speed ? Is K.E. conserved in the process ? If not from where does the change come out ?


#2