If a disc of mass m and radius r is reshaped into a ring of radius2r, the mass remining the same, the radius of gyration about centrodal axis perpendicular to plane goes up by a factor of

If a disc of mass m and radius r is reshaped into a ring of radius2r,

1.	If a disc of mass m and radius r is reshaped into a ring of radius2r, the mass remining the same, the radius of gyration about centrodal axis perpendicular to plane goes up by a factor of
Answer» `SQRT(2)` 2 `2 sqrt(2)` 4 Solution :The radius of GYRATION, `K_(D)=sqrt((I_(D))/(m))=sqrt(((1)/(2)mr^(2))/(m))=(R)/(sqrt(2))` `K_(R)=sqrt((I_(PR))/(m))=sqrt((m(2R)^(2))/(m))=2r` `:. (K_(R))/(K_(D))=2 sqrt(2)`.