Practice portal › Rotational Motion › Moment of Inertia
Asked in CBSE AIPMT 2012 Mains · Standard bodies and axis theorems
Given: four points of a uniform disc — A at the centre, C and D inside it, and B on the rim — with the axis perpendicular to the disc in each case.
Idea: the parallel axes theorem makes the moment of inertia grow with the distance of the axis from the centre.
I=I_cm+Md²=1/2MR²+Md²
I is largest when d is largest.
Of the four points, only B lies on the rim, at the greatest distance d=R.
So I is maximum about the perpendicular axis through B, where I=3/2MR².
Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.
Practise this with a timer