Two discs have same mass and thickness. Their materials are of densities d_(1) and d_(2). The ratio of their moments of inertia about an axis passing through the centre and perpendicular to the plane is

Two discs have same mass and thickness. Their materials are of densiti

1.	Two discs have same mass and thickness. Their materials are of densities d_(1) and d_(2). The ratio of their moments of inertia about an axis passing through the centre and perpendicular to the plane is
Answer» `d_(1) : d_(2)` `d_(2):d_(1)` `((d_(1))/(d_(2)))^(2)` `((d_(2))/(d_(1)))^(2)` SOLUTION :We have, `(PIR^(2)td)=m""(because "mass = density" xx "volume")` `R^(2)=(m)/(PID)` Now, `I=(1)/(2)mR^(2)=(m^(2))/(2pitd)or I prop (1)/(d)` `:.` The RATIO of moments of inertia, `(I_(1))/(I_(2))=(d_(2))/(d_(1))`.