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MHT CET · Physics · Rotational Motion

Three solid spheres each of mass ' \(M\) ' and radius ' \(R\) ' are arranged as shown in the figure. The moment of inertia of the system about YY' will be

  1. A \(\frac{16}{5} \mathrm{MR}^2\)
  2. B \(\frac{21}{5} \mathrm{MR}^2\)
  3. C \(\frac{7}{5} \mathrm{MR}^2\)
  4. D \(\frac{11}{5} \mathrm{MR}^2\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{16}{5} \mathrm{MR}^2\)

Step-by-step Solution

Detailed explanation

Moment of inertia of the upper sphere \(=\frac{2}{5} \mathrm{MR}^2\)
For each lower sphere M.I. \(=\frac{2}{5} \mathrm{MR}^2+\mathrm{MR}^2=\frac{7}{5} \mathrm{MR}^2\)
\(\therefore\) Total moment of inertia \(\mathrm{I}=\frac{2}{5} \mathrm{MR}^2+2 \times \frac{7}{5} \mathrm{MR}^2=\frac{16}{5} \mathrm{MR}^2\)