# The period of a pendulum

## Homework Statement

the period of a physical pendulum is ## 2\pi \sqrt{I/mgh}, ## where I is the moment of
inertia about the pivot point and d is the distance from the pivot to the
centre of mass. A circular hoop hangs from nail on a barn wall. The
mass of the hoop is 3 kilogram and its radius is 20 centimetre . If it
is displaced slightly by a passing breeze, what is the period of the
resulting oscillation.

## Homework Equations

What is the solution ?

## The Attempt at a Solution

I thank about as a motion of torsion pendulum, whose ## T= 2 \pi \sqrt{I/c} ##, with ## I = MR^2 ##, and c is the twisting coupling.