A disc of mass `M` and radius `r` is rotating with an angular velocity `omega`. If gently, two masses `m` each are placed at a distance `r//2` on either side of the axis of rotation, what will be the new angular velocity ?

Options

A. `(omega)/(2)`
B. `(momega)/(M+m)`
C. `(Momega)/(M+m)`
D. `(M+m)/(Momega)`

Answer

C

Explanation

`Iomega=I^(1)omega^(1)`
`therefore" "(MR^(2))/(2)omega=[(MR^(2))/(2)+2m((R^(2))/(4))]omega^(1)`
`therefore Momega=(M+m)omega^(1)" "therefore" "omega^(1)=(Momega)/(M+m)`