Finally. Done. With training level 07. I wanted to create a new pendulum object for this one and had a bit of trouble initially getting it to work the way that I wanted to. After getting a tip from a Box2D guru, I was able to get things working. The problem had to do with me creating an axle that had no fixture. When I did this, the pendulum rod quit swinging. Double plus ungood. You need to have a fixture in place or the fixtureless body constrains rotation.
So, yeah, WOOT! Here's a screenshot.