Time period and natural frequency

[svishal03]

A fundamnetal question here;

IS it that the terminologies natural time period and frequency are used only for simple harmonic motions and not for motions which are periodic/sinusoidal like an SHM?

 

[Astronuc]

A fundamnetal question here;

IS it that the terminologies natural time period and frequency are used only for simple harmonic motions and not for motions which are periodic/sinusoidal like an SHM?

Usually, natural frequency refers to the frequency of the fundamental mode.

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html#c3

 

[svishal03]

And when we say fundamental mode, it is always simple harmonic, right?

Am I right natural frequency and time period can be used for motions which have a periodicity?

 

[olivermsun]

Not just a periodicity but some clear reason why that frequency or period is more natural than any other. For example, the simple harmonic oscillator has a natural frequency which is determined by the ratio of spring constant to mass. Similarly a vibrating string has a fundamental frequency determined by the density, spring constant, and length.

The rotating Earth on the other hand is more or less periodic but there is no overwhelming reason why it wants to rotate at 1 cycle/day as opposed to any other frequency.