Electromagnetic braking: a simple quantitative model
  A calculation is presented which quantitatively accounts for the terminal velocity of a cylindrical magnet falling through a long copper or aluminum pipe. The experiment and the theory are a dramatic illustration of the Faraday's and Lenz's laws and are bound to capture student's attention in any electricity and magnetism course. 
Yan Levin, Fernando L. da Silveira, and Felipe B. Rizzato