  In investigating the relation between vorticity and gyroscopic precession, we
calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, Minkowski
metric and find out the vorticity vector of the specific observers is the
angular velocity of gyroscopic precession. Furthermore, considering space-time
torsion will flip the vorticity and spin-curvature force to opposite sign. This
result is very similar to the behavior of positive and negative helicity of
quantum spin in Stern-Gerlach force. It implies that the inclusion of torsion
will lead to analogous property of quantum spin even in classical treatment.
