A rod over two rotating cylinders

Two equal cylinders are rotating with opposite angular velocities. A bar is placed over them where it remains horizontal. The coefficient of dynamical friction between each cylinder and the bar is μ (mu in the simulation).

To get information about one element, put over it the mouse cursor.

Activities

Use the mouse to move a bit the bar center.
What kind of motion does its describe? (Select a positive value for N, say N = 100: does it ring a bell?)
Check Forces to see the forces between cylinders and bar.
Change μ and the distance between cylinders (by setting a or using the mouse on the center of the cylinder on the right). Does the oscillation period change according to the theoretical result you have to find?

This is an English translation of the Basque original for a course on mechanics, oscillations and waves.
It requires Java 1.5 or newer and was created by Juan M. Aguirregabiria with Easy Java Simulations (Ejs) by Francisco Esquembre. I thank Wolfgang Christian and Francisco Esquembre for their help.