And we found that these expressed in

terms of vibration systems parameters

that has stiffness of a spring.

And, interestingly,

it has the relation between natural frequency and

excitation frequency, squared.

I have to, okay, squared, and- 1.

So, in this expression, it is very interesting

that how much it accelerates with respect to unit

excitation force is very much related with 1 over k,

and this interesting frequency ratio.

So response depends very much on frequency ratio.

In other words, the excitation frequency has to

be always measured with respect to natural frequency.

Where the natural frequency f0

= 1/2 pi square root k/m,

m is the mass of, single degree

of freedom by system.

And look at very carefully again what it means, because we obtained the result