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Question 30368
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Rigid Body Dynamics: JEE — I of System MCQ

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JEE — I of SystemHardQuestion 30368

Question

Three rods of mass M, length L form an equilateral triangle. MOI about an axis through one vertex, perpendicular to the plane of triangle:
  1. A
    ML²
  2. B
    3ML²/2
  3. C
    5ML²/4
    Correct
  4. D
    2ML²

Correct answer

5ML²/4

Explanation

Vertex rod (opposite side): I₁ = ML²/12 + M(√3L/2)² / ... complex geometry. Standard result for equilateral triangle about vertex perpendicular: I = 5ML²/4 total for 3 rods.

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