A body of mass 1.5 kg rotating about an axis with angular velocity of `0.3 " rads"^(-1)` has the angular momentum of 1.8 kg `"m"^(2)"s"^(-2)`. The radius of gyration of the body about an axis is

Options

A. 2 m
B. 1.2 m
C. 0.2 m
D. 1.6

Answer

A

Explanation

We know that,
`L = I omega = M k^(2) omega " "...(i) (because I = MK^2)`
Now put the given values in Eq. (i), we get
`1.9 = 1.5 xx K^2 xx 0.3`
`K^2 = (1.8)/(1.5 xx 0.3)`
`K^2 = (1.8)/( 0.45) = 4`
`K =2`m