A spring loaded gun shoots a brass ball into the
cup at the end of a pendulum arm. A catch attached to the cup engages with
a toothed rack to hold the pendulum arm up at the angle of maximum ascent.
The rack has a scale to indicate the angle.
Click
on Image for Quicktime Animation
This demo can be found in cabinet B on shelf 5 of the UCSD PUL Demo Room
(WLH 2015).