  Although there is no force on the electron in Aharonov-Bohm solenoid effect,
the electron exerts a force on the solenoid related to the inequality of action
and reaction forces of two subsystems in three-system configuration. The AB
phase which is related to the force exerted by the electron on the solenoid .
The momentum changes of the mechanical oscillator are equal in magnitude and
opposite in sign to the changes in the momentum of the em fields. It is
proposed to investigate momentum changes of "micro" bodies producing magnetic
fields in AB systems which will clarify the nature of these effects. The
problem of magnetic fields shielded from the electron wave packet is also
discussed.
