A physical pendulum is any pendulum where the mass is NOT all concentrated at one point.

For a physical pendulum   w

=

(

m g h I

)

½

Here h is not the length of the pendulum, but the distance from the point of rotation to the pendulum's center of gravity.

If the physical pendulum is a rod of length L supported at one end:

h

=

L 2

and

I

=

1 3

mL2

This would give an angular frequency of:

w

=

(

3g 2L

)

½

This has the same frequency as a simple pendulum with a length of 2L/3.