spring (SI unit: newtons/metre or N/m)
* = mass (SI unit: kg).

While doing a modal analysis, the frequency of the 1st mode is the fundamental frequency.

This is also expressed as:

\,}}

where:
* ₀ = natural frequency (SI unit: hertz)
* = length of the string (SI unit: metre)
* = mass per unit length of the string (SI unit: kg/m)
* = tension on the string (SI unit: newton)