- #1

- 71

- 0

## Homework Statement

You have ruler of length L and thickness 2d resting, in equilibrium , on a cylindrical body of radius r. Slightly unbalancing the ruler, and existing attrition between the surfaces prove that the ruler has a oscillatory motion of period:

[tex] T = 2\cdot \pi\cdot \sqrt{\frac{L^2}{12\cdot g\cdot (r-d)}} [/tex]

## Homework Equations

[tex]T=\frac{2\cdot \pi}{\omega}[/tex]

[tex]\tau= F\cdot r\cdot \sin(\varphi)[/tex]

## The Attempt at a Solution

I can't wrap my mind about the idea that the ruler won't immediately begin to fall. I can't figure out why the ruler would do a simple harmonic motion in the first place.