A fixed torque produces larger alpha when inertia is smaller. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Large inertia changes spin slowly
The same checked torque is 12 newton meters. Dividing by inertia 12 gives angular acceleration 1 per second squared.
α=12/12=1
Half the inertia gives twice the alpha
The same checked torque is 12 newton meters. Dividing by inertia 6 gives angular acceleration 2 per second squared.
α=12/6=2
Small inertia gives the largest alpha
The same checked torque is 12 newton meters. Dividing by inertia 3 gives angular acceleration 4 per second squared.