Question
A sphere of radius R is cut from a larger solid sphere of radius 2 R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is:
A sphere of radius R is cut from a larger solid sphere of radius 2 R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is:
C. 7 57
aligned & I _1= 2 5 M (2 R )^2 \\ & I _2= 2 5 mr ^2+ md ^2 \\ & = 2 5 ( M 8 ) R ^2+ M 8 ( R )^2 \\ & = 7 MR ^2 40 \\ & I = I _1- I _2= 8 MR ^2 5 - 7 MR ^2 40 = 57 40 MR ^2 aligned I _2 I _1 = 7 57
Related: Physics — Rotational Motion · All PYQ Banks