Q.

A ring and a solid sphere rotating about an axis passing through their centers have the same radii of gyration. The axis of rotation is perpendicular to plane of the ring. The ratio of radius of the ring to that of the sphere is 2x. The value of x is ________ .                 [2023]


Ans.

(5)

For ring, I=mR12=mK12

 Radius of gyration K1=R1

For solid sphere, I'=25m'R22=m'K22

  Its radius of gyration  K2=25R2

 K1=K2

 R1=25R2

 R1R2=25

 x=5