A thin rod of total mass M and length L is bent at its midpoint into two perpendicular halves. Find its moment of inertia about an axis through the bend and normal to their plane.
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Question

A thin rod of total mass M and length L is bent at its midpoint into two perpendicular halves. Find its moment of inertia about an axis through the bend and normal to their plane.

G1 Physics · Accepted Answer

Step 1: Each segment has mass M/2 and length L/2. Step 2: Inertia of each about the bent end is (1/3)(M/2)(L/2)²=ML²/24. Step 3: Two segments give ML²/12. Step 4: The source printed answer C treats each half as though it had mass M; physical total mass is M, so the correct option is B. Final answer: B — ML²/12.