When it vibrates in several sections, each section moves in the opposite way to its neighbours.
This hammer is arranged so that when the armature vibrates it gives little blows to the underside of the tube and shakes up the filings.
I) be a small portion of a bell which vibrates to and fro from CD to EF and back.
Each section then vibrates, and its amplitude goes through all its values in time given by 21rUT/A =2r, or T =A/U, and the frequency is U/A.
Therefore with equal weights a balance vibrates more slowly the more sensitive it is, and therefore weighing by a sensitive balance is a slower process than with a less sensitive one.