A boy is seated in a revolving chair revolving at an angular speed of 120 rpm. By some arrangement, the boy decrease the moment of inertia of the system from `6 kg m^(2)` to `2 kg m^(2)`. What will be the new angular speed ?

Explanation

Here, `omega_(1) = 120` rpm
`I_(1) = 6kg m^(2), I_(2) = 2 kgm^(2), omega_(2) = ?`
Acc. To the principle of conservation of angular
momentum, `I_(2)omega_(2) = I_(1)omega_(1)`
`:. omega_(2) = (I_(1)omega_(1))/(I_(2)) = (60 xx 120)/(2) = 360` rpm