  It is shown that the spin of pi (0), eta, Lambda, Sigma (+,-,0), Xi (-,0),
Lambda-c (+), Sigma-c (0), Xi-c (0), and Omega-c (0) mesons and baryons can be
explained by the sum of the angular momentum vectors and spin vectors of the
electromagnetic waves which are in these particles according to the standing
wave model. The spin of the pi (+,-), K (+,-,0), D (+,-,0), and D-S (+,-)
mesons and of the neutron is the sum of the angular momentum vectors of the
oscillations and of the spin vectors of the neutrinos and the electric charges
which are in the cubic lattice of these particles. Spin 1/2 is the consequence
of the superposition of two perpendicular standing waves of equal frequencies
and amplitudes shifted in phase by pi/2. The spin of the antiparticles of the
mesons and baryons is the same as the spin of the ordinary particles.
