For a circular disc made of iron and aluminium, which radial arrangement maximizes the moment of inertia about the geometric axis?
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Question

For a circular disc made of iron and aluminium, which radial arrangement maximizes the moment of inertia about the geometric axis?

G1 Physics · Accepted Answer

Step 1: To maximize I=∫r² dm, put the denser/heavier iron at larger radius and lighter aluminium near the centre. Step 2: This describes aluminium at the interior and iron on the outside; choice A (also equivalently D in wording) is the source-keyed option. Final answer: A — aluminium inside and iron outside.