InterviewSolution
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InterviewSolution
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A circular disc `X` of radius `R` is made from an iron of thickness `t`, and another disc `Y` of radius `4R` is made from an iron plate of thickness `t//4`. Then the relation between the moment of mertia `I_(x)` and `I_(Y)` is :A. `I_(y)=32 I_(x)`B. `I_(y)=16 I_(x)`C. `I_(y)=I_(x)`D. `I_(y)=64I_(x)` |
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Answer» Correct Answer - D Mass of disc (X), `mx=piR^(2)t rho` Where `rho` =density of material of disc `:. I_(x)=1/2 m_(x)R^(2)=1/2 R^(2)t rho R^(2)` `I_(x)=1/2 pi rho R^(4)......(i)` Again mass of disc (Y) `m_(y)=pi=(4R)^(2)t/4 rho=4piR^(2) t rho` and `I_(y)=1/2 m_(y)(4R^(2))=1/2 4piR^(2)t rho.16 R^(2)` `rArr I_(y)=32pi t rho R^(4)......(ii)` `:. (I_(y))/(I_(X))=(32pi t rho R^(4))/(1/2 pi rho t R^(4))` `rArr =64` `:. :. I_(Y)=64 I_(X)` |
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