Damping is provided by an aluminum rod passing through a magnet gap.  The gap spacing can be adjusted to vary the damping constant.

Twist the spade lug until the mass bar is square in the hole.

For phase and amplitude measurements, mass bar must hang so that, at equilibrium, its center line is aligned with the photogate in the guide.  To do this:

1. Note that the phase LED flashes on and off when the center line passes through the photogate.  Rotate the drive wheel until the flashing LED is at the zero degree mark on the phase scale.
2. Adjust the cord length, using the plastic friction clip, so that small oscillations of the bar cause the LED to turn on and off.  Use the screw at the top of the column for fine adjustments.