Length of Pendulum: Does COM Matter?

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The discussion centers on whether the length of a pendulum should be measured from the center of mass (COM) or the bottom of the pendulum bob. It highlights that the formula for the period of a simple pendulum, T=2pi*sqrt(L/g), indicates that the length (L) is crucial for determining the period. A specific example illustrates that a 50cm pendulum and a 1m ruler pivoted near the end can have the same period, emphasizing the importance of the pivot point. The conclusion drawn is that measuring from the COM provides a consistent basis for calculating the pendulum's behavior. Understanding this distinction is essential for accurate physics calculations.
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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!
 
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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)
 
Thank you! That clears it up perfectly.
 

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