Voice coils work according to the Newton’s second law: F=ma
The inertial shaker is slightly different compared to voice coil but works with the same equation. The armature is the moving mass “m”. IS-40 has an armature weight of 0.16kg. When a signal is passed through the coil, it moves the armature up and down with an acceleration “a”. The multiplication “F” is the force rating of the inertial shaker.