Massachusetts Institute of Technology
Sign in

MIT Physics Demo -- Pendulum and Magnet

A solid copper pendulum is mounted between the poles of an electromagnet (solenoid). The pendulum is set into motion, and then the magnets are turned on. The magnets induce eddy currents in the copper which oppose the motion of the pendulum. The pendulum quickly slows to a stop, demonstrating an effect called eddy current braking. Eddy current brakes are widely used in trains and roller coasters.

When a copper pendulum with strips cut into it is swung between the same magnets, it is not slowed nearly as much as the solid pendulum. This is because the cuts in the copper prevent large eddy currents from forming. Only eddy currents smaller than the strips of copper can be formed.

Comments (1)

why does the perforated copper plate slow down less than the solid pendulum?

Posted over 8 years by Anonymous User

You need to log in, in order to post comments.

MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated almost 7 years ago

Created
April 15, 2008 11:50
Category
Tags
License
Creative Commons Attribution-NonCommercial (What is this?)
Additional Files


Viewed
48521 times

More from MIT Department of Physics Technical Services Group

Confetti and the Van de Graaff Generator

Confetti and the Van de Graaff Gene...

Added over 8 years ago | 00:00:55 | 46837 views

Ripple Tank: Interference of Two Point Sources

Ripple Tank: Interference of Two Po...

Added 8 years ago | 00:01:41 | 50812 views

MIT Physics Demo -- Jacob's Ladder and the Melting Nail

MIT Physics Demo -- Jacob's Ladder ...

Added over 9 years ago | 00:01:26 | 59523 views

Two Dimensional Collisions

Two Dimensional Collisions

Added 8 years ago | 00:01:19 | 49439 views

MIT Physics Demo -- Exploding Wire

MIT Physics Demo -- Exploding Wire

Added 9 years ago | 00:02:00 | 66849 views

Physics Demo -- Superconductor

Physics Demo -- Superconductor

Added over 9 years ago | 00:00:56 | 58045 views