NEET2025PhysicsRotational MotionActual
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:
Options
- A7 8
- B7 40
- C7 57
- D7 64
Correct answer
C. 7 57
Step-by-step solution
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