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The ratio of radius of gyration of a solid sphere of mass M and radius R about its own axis to the radius of gyration of the thin hollow sphere of same mass and radius about its axis is

Asked in NEET 2023 · Radius of gyration and numericals

Answer: (4) None of Above

Step-by-step solution

Given: solid sphere and thin hollow sphere, same M and R, each about a diameter.

Idea: the radius of gyration is defined by I=Mk², so k=√I/M.

Solid sphere: I=2/5MR², so k₁=R√2/5.

Thin hollow sphere: I=2/3MR², so k₂=R√2/3.

(k₁)/(k₂)=√(2/5)/(2/3)=√3/5=√3:√5≈0.775.

That is neither 5:3, nor 2:5, nor 5:2, so none of the listed ratios is correct.

Why the other options are wrong

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