Incompetnce

I had to to an exercise sheet for the first year students. As most of the exercises I found in books were either shite or wrong (or both), I tried to do some of my own. I dug out the paper of Henry Cavendish, were he determined the density of the earth with his famous torsion balance. I calculated everything with his measurements. It took about two days until I had understood what he did and ended up at a Gravitational Constant which made sense.

I made an exercise out of it. I had to simplify it a bit, because the students did not yet know the torsion pendulum. While simplifying it, I introduced a couple of errors, which went unnoticed but made the complete calculation bollocks.

I had another exercise on an hammer bouncing off the floor where I mixed up elastic and in-elastic bounces.

When doing the example solution to the problems, the one which all other tutors would read and use to correct the exercises, I made about every possible error and mis-calculated about every quantity at least twice. So it took me about 8 or 9 iterations (all sent around to all tutors) to have a solution sheet, which was nearly right (I didn't find the errors myself, btw.). I think I should quit doing my PhD, hand back my diploma and do a ritual suicide. That would be the correct outcome of this. As I have met people who are even more incompetent and got away with it, I will wait a bit, maybe I can get away with it too...