  Liquid-solid phase transition and the change of the frictional force of a
system with two hard spheres in a two-dimensional rectangular box are
discussed. Under controlling the pressure or the supply of energy from the
wall, the solid like state, the solid-liquid temporal coexistence state, and
the liquid like state are alternatively observed. The frictional force which
works on particles and the mobility of the system are measured under the supply
of the energy with an asymmetric external force. Characters of frictional
forces for the 0 mobility state and that for the large mobility state are
obtained like, respectively, that of the static and the dynamic frictions of
solid-on-solid system. The strong temperature dependency is also observed in
the profile of the relation between the above frictional force and the
mobility. From above results, the relation between the friction and the
velocity of a plate on granular layers which includes the hysteresis loop
[S.Nasuno et al.,Phys. Rev. Lett {\bf 79} (1997) 949 et. al.] is discussed.
