Sample 1Medium
A thin uniform rod of mass 0.6 kg and length 1 m is drawn with an axis passing through one of its ends, perpendicular to the rod. A second, dashed axis is drawn parallel to the first through the rod's midpoint. What is the moment of inertia about the axis through the end?
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The answer is C.
About the midpoint I = ML²/12 = 0.05 kg m². The parallel axes theorem adds M(L/2)² = 0.15 kg m², giving ML²/3 = 0.2 kg m².
- A.
0.05 kg m² is the moment of inertia about the central axis, not the end.
- B.
0.6 kg m² is ML², as if all the mass were at the far end.
- D.
0.15 kg m² is only the M(L/2)² term of the parallel axes theorem.
NCERT: Class 11 Physics, Chapter 6