Massachusetts Institute of Technology
Sign in | Create Account

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 almost 6 years by Anonymous User

You need to log in, in order to post comments. If you don’t have an account yet, sign up now!

MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated over 1 year ago

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


Viewed
40411 times

More from MIT Department of Physics Technical Services Group

Steel Ball Dropped in a Viscous Fluid

Steel Ball Dropped in a Viscous Fluid

Added 3 years ago | 00:02:03 | 11225 views

Ripple Tank: Single and Double Slit Diffraction and Interference

Ripple Tank: Single and Double Slit...

Added over 5 years ago | 00:03:05 | 57529 views

Soap Film Oscillation

Soap Film Oscillation

Added over 5 years ago | 00:04:27 | 45340 views

Charge and Electric Field of a Hollow Conductor

Charge and Electric Field of a Holl...

Added 3 years ago | 00:01:54 | 7952 views

Fluorescent and Neon Tubes in an Electric Field

Fluorescent and Neon Tubes in an El...

Added over 4 years ago | 00:02:02 | 33420 views

Simulation of Magnetic Domains

Simulation of Magnetic Domains

Added over 2 years ago | 00:01:54 | 4250 views