A rotating flywheel has moment of inertia 12.0 kg⋅m² for an axis along the axle about which the wheel is rotating. Initially the flywheel has 30.0 J of kinetic energy.
It is slowing down with an angular acceleration of magnitude 0.400 rev/s2.
Part A
How long does it take for the rotational kinetic energy to become half its initial value, so it is 15.0 J?
Express your answer to three significant figures and include the appropriate units.