Length of Pendulum: Does COM Matter?

[AnthroMecha]

Homework Statement

Does it matter whether you measure the length of the pendulum to the center of mass of the ball or to the bottom of the ball

Homework Equations

T=2pi*root(L/g)

The Attempt at a Solution

I can see that L (length) is a factor, but I'm not sure why it matters if it's taken from the COM or not??

Any help is appreciated!

 

[technician]

It is essential! A simple pendulum (small mass on the end of a massless string) of length 50cm will have the same time period as a wooden ruler of length 100cm (1 metre).
The 1m ruler must be pivoted as near the end as possible.
The centre of mass of a uniform wooden ruler is at the middle (50cm mark)

 

[AnthroMecha]

Thank you! That clears it up perfectly.