Rotational kinetic energy is KE = 0.5 * I * omega^2, the angular analog of 0.5 * m * v^2, keeping the half factor that comes from integrating torque over angle. The arithmetic is exact only for the stated inertia and angular speed in the ideal rigid-body model. Real systems add distributed-mass geometry, slipping, friction, bearing losses, axis alignment, sensor calibration, finite precision, and measurement uncertainty.
Rotational kinetic energy uses one half times inertia times spin squared. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Rotational kinetic energy has a half factor
With inertia 8 and spin 3, the rotational energy is 36 joules.
Krot=1/2×8×32=36J
Energy stays in joules
The energy label is 36 joules, while torque elsewhere stayed in newton meters.