[Virginia Tech Department of Physics]

Lecture Demonstrations


M87: Wilberforce Pendulum


Purpose: To demonstrate coupled oscillation modes.



When the Wilberforce Pendulum is initially displaced in the vertical direction, it oscillates in a purely up-and-down motion. The translational oscillation gradually transfers to a purely torsional mode and then back to the translational mode. The translational and torsional periods must be the same. This is accomplished by adjusting the position of the masses on the crossbar.

The motion of the Wilberforce Pendulum can be recorded using DataStudio software. The vertical position, velocity, and acceleration are measured with a Motion Sensor placed below the pendulum. A laser and a Laser Switch measure the angular speed in the torsional mode as the spokes of the wheel break the laser beam. The transition between modes can be seen on a graph. A Force Sensor attached to the end of the spring measures the spring force as the pendulum oscillates. The force can be graphed in real-time as a function of position to determine the spring constant and the theoretical period. The period of oscillation is about one second.

Equipment List: Storage Location: CHEMP 130A


Pasco Wilberforce Pendulum D2.4


Manual   Setup Notes: M87 PIRA #:
Manufacturer(s): Pasco Scientific # ME-8091 Other school's Demonstration web pages



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