The same mass near the axis has a smaller rotational ledger. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Closer mass has much less inertia
With the same 2 kilogram mass at radius 1 meter, the inertia is only 2 kilogram meter squared.
I=2×12=2kgm2
Radius controls how hard spin is to change
The inertia drops from 18 to 2 when the mass moves inward.