  We investigate the laws of thermodynamics and weak cosmic censorship
conjecture in the normal and extended phase space of a Kerr-AdS black hole by
analyzing the energy-momentum relation of the absorbed fermion dropping into
the horizon. In the normal phase space, the first law, second law as well as
the weak cosmic censorship conjecture are found to be valid in all the initial
states of the black hole. However, in the extended phase space, although the
first law and weak cosmic censorship conjecture are still valid, the second law
becomes more subtle. We find that the validity or violation of the second law
depends on the spin parameter, the radius of the AdS spacetime, and their
variations. In addition, in the extended phase space, the configurations of the
extremal and near-extremal Kerr-AdS black holes are unchanged as the fermions
are absorbed since the final and initial states are the same.
