# Resistance of a disk

1. Apr 3, 2007

### Gyroscope

1. The problem statement, all variables and given/known data
A disk with width b and radius a.
An element of resistance is:

$$dR=\rho \frac{2\pi r}{bdr}$$

How do I integrate this?

2. Relevant equations

3. The attempt at a solution

2. Apr 3, 2007

### Staff: Mentor

I don't understand your volume element. You are trying to get the total resistance between what two places? A point on one edge of the disk to a point on the other side, or from the center out to the perimiter, or what?

3. Apr 3, 2007

### Gyroscope

It's the sum of the resistances of each ring of the disk.