Model railroad type example Sn3.5 is as follows, S (scale) being the prefix to n (narrow gauge) followed by 3.5 (prototype track gauge in feet), 3 and 1/2 feet, or 42 inches, which in Sn3.5 equates to actual modeling track width of .649 - .672 thousandths, 16.5 - 17.1 mm.
Definition of harmonic. 1  1a : overtone; especially : one whose vibration frequency is an integral multiple of that of the fundamentalb : a flutelike tone produced on a stringed instrument by touching a vibrating string at a nodal point.
The frequency of the periodic motion is known as a vibration frequency, and the typical frequencies of molecular vibrations range from less than 10 12 to approximately 10 14 Hz.he coordinate of a normal vibration is a combination of changes in the positions of atoms in the molecule. When the vibration is excited the coordinate changes sinusoidally with a frequency Î½, the frequency of the vibration.