Question

A boy stands on a freely rotating platform with his arms extended. His rotation speed is 0.3 rev/s, when he draws in, his speed increases to 0.5 rev/s, then the ratio of his moment of inertia in these two cases will be
A. `3 : 5`
B. `5 : 3`
C. `9 : 25`
D. `25 : 9`

Answer 1

Correct Answer - B
`I_(1)omega_(1)=I_(2)omega_(2)`
`KE_(2)=(1)/(2)I omega^(2)`