question_answer

The radius of gyration of solid sphere of radius R about a certain axis is also equal to R. If r is die distance between the axis and the centre of the sphere, then r is equal to

A)                  R                                           

B)                  0.5 R

C)                  \[\sqrt{0.6}\]R                                 

D)                  zero

Correct Answer: A

Solution :

                 The radius of gyration of a body about a given axis equal to root mean square distance. Here, there is be only one axis                 \[K=\sqrt{\frac{{{r}^{2}}}{n}}\]                 \[K=\sqrt{{{r}^{2}}}\]     \[[\because n=1]\]                 \[R=r\]