If we are dealing with a resistance to acceleration, we are witnessing an increase of inertial mass of the test object, determined by an electric and/or magnetic phenomenon, but without a corresponding increase in gravitational mass.
(we; are dealing; with a resistance to acceleration) (we; are witnessing; an increase of inertial mass of the test object) (the test object; determined; by an electric and/or magnetic phenomenon)
we we the test object
are dealing are witnessing determined
with a resistance to acceleration
an increase of inertial mass of the test object
by an electric and/or magnetic phenomenon