# Deriving the Equation for Period of Simple Pendulum? Is my attempt correct?

1. Oct 1, 2011

### amd123

1. The problem statement, all variables and given/known data
I have to derive an equation with the following variables:
T= period
m= mass
Theta= angle
l= length

and I was told to think of the period as the perimeter of a circle.

2. Relevant equations

3. The attempt at a solution
$$C=2\pi r,C/2=\pi r,d=\pi r,(at^2)/2=\pi r,t=\sqrt{\frac{2\pi r}{Ef/m}},t=\sqrt{\frac{2\pi rm}{sin\Theta r }}$$

2. Oct 1, 2011

### rock.freak667

It is simpler to just draw the pendulum's arc and then use then use the tangential component as the resultant force (F=ma).

This will help you prove that for small angles, the motion is simple harmonic and then the period will be easier to find.

3. Oct 2, 2011

### amd123

I have not come across any of the terminology you have just said.
I doubt I would be allowed to use that method.

Could you describe it in another way or comment on my attempt?