Concepts

Normal modes, coupled oscillations

Overview

When oscillating, the pendulum slowly shifts between torsional and vertical modes of oscillation. When stretched down, the spring applies a torque to the mass to help it unstretch. When compressed up, the spring applies a torque the other way. This leads to torsional motion. The converse happens when starting from torsional motion, leading back to vertical oscillations.

Details

Equipment

• [1] Wilberforce pendulum
  
• [1] Lab jack

Important Notes

• Make sure that when transporting the demo, the lab jack prevents the pendulum from swinging wildly.

Script

1. Start the pendulum oscillating vertically.
2. Wait for it to change to torsional oscillations.
   

Additional Resources