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Asked in JEE Main 20th July 2nd Shift 2021 · Rolling on an incline
Rolling without slipping from rest through a height h: v²=(2gh)/(1+k) with k=I/(MR²).
Ring: k=1, so vᵣ²=gh.
Solid cylinder: k=1/2, so v_c²=(4gh)/3.
(vᵣ²)/(v_c²)=3/4, so (vᵣ)/(v_c)=(√3)/2.
Comparing with (√x)/2 gives x=3.
"Of the same material" tells you the densities match, so the masses differ — but mass cancels out of v, so it never matters.
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