# Period for Oscillating Ring

## Homework Statement

A thin 0.50-kg ring of radius R = 0.60 m hangs vertically from a horizontal knife-edge pivot about which the ring can oscillate freely.

If the amplitude of the motion is kept small, what is the period?

## Homework Equations

T = 2pi / ω

Not sure what others...

## The Attempt at a Solution

I have no idea what a "horizontal knife-edge pivot" is (I tried to Google it with no success) so I actually don't know where to begin with this problem because I cannot understand what is happening. I'd appreciate an explanation as to what the question means.

ehild
Homework Helper

## Homework Statement

A thin 0.50-kg ring of radius R = 0.60 m hangs vertically from a horizontal knife-edge pivot about which the ring can oscillate freely.

If the amplitude of the motion is kept small, what is the period?

## Homework Equations

T = 2pi / ω

Not sure what others...

## The Attempt at a Solution

I have no idea what a "horizontal knife-edge pivot" is (I tried to Google it with no success) so I actually don't know where to begin with this problem because I cannot understand what is happening. I'd appreciate an explanation as to what the question means.
This is the arrangement. The ring hangs from a knife, the edge of the knife is the pivot. It is a "physical pendulum". http://hyperphysics.phy-astr.gsu.edu/hbase/pendp.html

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Joshua A and scottdave
This is the arrangement. The ring hangs from a knife, the edge of the knife is the pivot. It is a "physical pendulum". http://hyperphysics.phy-astr.gsu.edu/hbase/pendp.html

View attachment 215582
Thank you! I figured out the question now.

Hint for anyone who may stumble upon this thread in the future: when using the equation on the HyperPhysics page, note that it says Isupport. Use the parallel-axis theorem to help you find this.