I too found bikecalculator. A bit disheartening on the physics front but then Ben comes in with real life knowledge and there was much rejoicing. The capillaries guy may in fact be closer to right than I thought.

This is all started when I was chasing this twig of a man through some moderate rolling hills. He was unaware I was racing him of course but it makes it fun. When I finally passed him I saw he was average height and maybe 140lbs soaking wet. Also he had to be at least 60 years old