Re: What's the formula for calculation body's own frequency?

What you say is partially right Miha. Though all bodies can vibrate at 
almost any frequency, they also have a set of frequencies that they can 
naturally vibrate at - with the least amount of energy.

The lowest of these frequencies is called the fundamental frequency. The 
other frequencies called harmonics are multiples of this frequency.

As with most things in physics there are equations to calculate the 
natural frequencies various different things

For instance for a stretched string like in a piano the equation is



Where f is the natural frequency,F is the tension,u (mu) is the mass per 
unit length of the string, L is the length of the string and n is integer 
(1,2,3,4 ...)

When n=1 this is known as the fundamental frequency.

Or likewise for a solid rod the equation is,



Where the letters are the same as before but Y is youngs modulus a measure 
of the material strength and under that is the symbol for density Rho

As to finding the the natural frequency of your body, it's bit more 
difficult

Your body could be treated as a collection of different objects and then 
theoretically the fundamental frequency of your body would be the lowest 
common multiple of these objects fundamental frequncies.

I have no idea whether or not any one has actually done this.

You will find more on this topic at
 http://www.britannica.com/bcom/eb/article/5/0,5716,117555+20+109557
,00.html