Two identical spherical balls of mass M and radius R each are stuck on two ends of a rod of length 2 R and…

Two identical spherical balls of mass M and radius R each are stuck on two ends of a rod of length 2R and mass M(see figure). The moment of inertia of the system about the axis passing perpendicularly through the centre of the rod is


  1. 20915MR2.
  2. 15215MR2.
  3. 13715MR2.
  4. 175MR2.

Solution

Applying parallel axis theorem for the balls,
Ib=25MR2+M2R2


Itotal=2Ib+IR
Itotal=25MR2+M2R2×2+M122R2

Itotal=13715MR2

Asked in: JEE Main 2019 (10 Jan Shift 2)

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