Thirty years after engineering school, I still have occasional nightmares. In my dream, a professor teaching differential equations is standing at a 40 foot long blackboard, back to the class, speaking in a barely audible monotone...
Pendulum (mathematics) - Wikipedia, the free encyclopedia
Actually, I do remember fondly the pendulum demonstration from freshman physics. It was held in a cavernous lecture hall with exposed ceiling beams. When we arrived for class, there was a bowling ball suspended on a 30 ft. rope, laying at rest just above the lectern at the center of the stage.
Two tall ladders were set up - stage left and stage right. I don't remember [-]all[/-] any of the details of the physics, but midway through the lecture the prof climbed up one of the ladders and continued to talk. A short time later, the grad student grabbed a crook of some sort and pulled the bowling ball toward the other ladder.
You can guess the rest...professor makes his key point about conservation of energy or whatever just as the bowling ball is released and begins a looonnng, slow sweep across the stage toward his head. He didn't flinch at all, of course. He just kept right on going into his next point about the motion of the pendulum.
This was early in the semester. After a round or two of this prof's tests, the demonstration might have been too risky due to the possibility of the students moving the ladders or paying off the grad student.
