Angular velocity and momentum are not parallel

A dumbbell is spinning around the fixed vertical axis Z with constant angular velocity ω. The angle between the rod and the vertical is θ. .

Activities

  1. Make sure you understand the motion of the rod and the two masses (it may help enabling trajectories and using the mouse or the cursors to change the point of view).
  2. How should be displayed the angular momentum and the external torque necessary to keep ω constant?
  3. Enable vectors to check your answer.
  4. When would be parallel angular velocity and momentum?
  5. Change ω to check your answer.


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.