SUBJECT: The Falling Magnet Applet
NOTE: You must be connected to the Internet the first time you view this simulation, at which point the codebase for all the simulations will be downloaded to your computer. This process make take a few minutes, as the codebase is roughly 9MB in size. Subsequent viewings of the applets will run from your local copy.
DESCRIPTION: This applet shows the dynamics of a magnet falling on the axis of a fixed conducting non-magnetic ring . As the magnet falls under gravity towards the ring, the changing magnetic flux through the ring gives rise to a current which is in a direction such as to slow the fall of the magnet, by Lenz's Law. The ring has mass m, resistance R, and self-inductance L, and the magnet has magnetic dipole moment M. You can vary the resistance of the ring and the strength of the magnetic dipole moment to see how these parameters affect the dynamics of the magnet. If the resistance is zero and the dipole moment is strong enough, the magnet will levitate above the ring. If the resistance is non-zero, even though small, the magnet will eventually fall past the ring. We also show the induced current in the ring in the meter on the lower left.
VISUALIZATION: Start Simulation (you must have Java™ J2SE v1.4+ JRE installed. Mac OS X users need the Java3D update.)