NEET2015PhysicsRotational MotionActual
Three identical spherical shells, each of mass m and radius r are placed as shown in the figure. Consider an axis X X ′ which is touching the two shells and passing through the diameter of the third shell. The moment of inertia of the system consisting of these three spherical shells about X X ′ axis is:
Options
- A11 5  m r 2
- B3 m r 2
- C16 5 m r 2
- D4 m r 2
Correct answer
D. 4 m r 2
Step-by-step solution
Total moment of inertia of the system, I + I 1 + I 2 + I 3 I 2 = I 3 = 2 3 m r 2 + m r 2 = 5 m r 2 3 I 1 = 2 3 m r 2 ∴ I = 2 × 5 m r 2 3 + 2 3 m r 2 I = 12 m r 2 3 = 4 m r 2