NEET2026PhysicsRotational MotionActual
A solid sphere A of radius R and mass M is attached at a point to a smaller solid sphere B of radius r
Options
- A0
- B(M-m)(R+r)^2
- C(m-M)(R+r)^2
- D(m-M)(R-r)^2
Correct answer
C. (m-M)(R+r)^2
Step-by-step solution
The distance between the centres of the two spheres A and B is d = R + r . Let I_ A, cm and I_ B, cm be the moments of inertia of spheres A and B about their respective vertical centroidal axes. For solid spheres, I_ A, cm = 2 5 MR^2 and I_ B, cm = 2 5 mr^2 . The moment of inertia of the system about a vertical axis passing through the centre of A is given by the sum of the moment of inertia of A about its own centre and the moment of inertia of B about the centre of A . Using the parallel axis theorem: I_A = I_ A,