Moment of inertia changes linearly with mass and quadratically with radius.
Moment of inertia changes linearly with mass and quadratically with radius. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
One-meter radius gives two inertia units
Mass 2 kg at radius 1 m gives inertia 2 kilogram meter squared.
I=2×12=2
Doubling radius quadruples inertia
Mass 2 kg at radius 2 m gives inertia 8 kilogram meter squared.
I=2×22=8
Doubling mass doubles the already-squared row
Mass 4 kg at radius 2 m gives inertia 16 kilogram meter squared.