# Magnetic ball falling inside conducting tube

1. Jul 15, 2012

### masterjoda

1. The problem statement, all variables and given/known data
I have a magnetic ball with magnetization M, mass m and radius R that starts to fall from rest through conducting tube of radius a little big larger than R, thickness $\Delta$ and conductivity $\sigma$. The ball is not rotating, it said that magnetization is oriented vertically down.

2. Relevant equations
Professor send me this problem, usually I know how to solve the problems that he sends me, but his one I don't know even how to start.

2. Jul 15, 2012

### CWatters

3. Jul 19, 2012

### masterjoda

They here use approximation with two monopoles but in my case I have a sphere and I think I sound me approximation with a one dipole but I don't know how to write flux then?