# How to Measure G with a Compound pendulum

For my Advanced Higher Physics Investigation i am measuring acceleration due to gravity. Having already done it with a simple pendulum my teacher says i have to do the same with a "Compound Pendulum". I was wondering how to do this and also how to make a compound pendulum with a steel rod.

Many thanks Ross.

A compound pendulum is one where the rod is not massless, and may have extended size; that is, an arbitrarily shaped rigid body swinging by a pivot. In this case the pendulum's period depends on its moment of inertia I around the pivot point.

T=2*Pi*Sqrt(I/(m*g*L)) where I is the moment of inertia of the rod and L is the distance from the pivot to the center of mass. Measure the period and mass. Locate center of mass and measure distance to pivot. Determining moment of inertia could be the tricky part.

Hi thats great. Sorry for the slow reply, but i need to clear something up. Is the T the time taken for one oscilation?

Thanks

T is the period or how long to complete one complete cycle