The radius of gyration of a solid shapere of radius r about a certain axis is r. The distance of this axis from the centre of the shpere is

Options

A. r
B. `0.5` r
C. `sqrt(0.6)r`
D. `sqrt(0.4)r`

Answer

C

Explanation

`k=r`
`I=mr^(2)=(2)/(5)mr^(2)+md^(2)`
`implies r^(2)-(2)/(5)r^(2)=d^(2)impliesd^(2)=(3r^(2))/(5)`
`implies d=sqrt(0.6)r` .