I am always 2-3 puzzles behind trying to understand the answers and not sure when an answer has actually been slipped in.You guys are forcing me to put back on my thinking cap which has been off in physics for 40 years.I quess I am put in my place being a lowly chemistry major grad 35 years ago.Got any anatomical, neuro-musculo-skeletal quizes?I am out of my league here but am enjoying the thread immensely although I have a lot of "Duh" moments.Fun to be an observor even though I wish I could play with the big boys.