Rotational and linear velocities - conveyor belt system

I've created a simple conveyor belt system. The belt contains two cogs, one at each end, and a couple of simple elongated cubes to represent the belt itself. The problem I have is matching the speed of objects dropped onto the belt with the rotational speed of the cogs.

How can I convert the rotational movement to linear velocity? I've found code to calculate the RPM but I don't know how to find out the velocity of the outside edge of the cog.

Edit: Nevermind, I was able to figure it out for my setup.

Code (CSharp):

1. var _distance = Vector3.Distance(beltPivot.transform.position, transform.position);
2.  
3. // Get the RPM - in another function, so not included
4.  
5. var _circumference = _distance * (2 * Mathf.PI);
6. var _linearVelocity = _rpm * _circumference;