Angular acceleration changes only after both torque and inertia sources close. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Base torque over inertia gives alpha two
Torque 12 newton meters divided by inertia 6 gives angular acceleration 2 per second squared.
α=12/6=2
Doubling torque doubles alpha
Torque 24 newton meters divided by inertia 6 gives angular acceleration 4 per second squared.
α=24/6=4
Doubling torque and inertia returns alpha two
Torque 24 newton meters divided by inertia 12 gives angular acceleration 2 per second squared.