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| I'm not so sure. The lake is 40.3 miles around. To do it in 1.5 hour would require 26.9 mph (43.4 kph). The power required by the cyclist to maintain this speed is dominated by the air drag, which is proportional to the speed squared. What this means is it takes about 77% more power to increase your speed by 33%!
For comparison (here we go again  ), Lance Armstrong won a 55km (34 mile) time trial at an average speed of 46.4 kph (28.8 mph). I would guess Lance could do Zurichsee in 1:28 (with his 3kg time trial bike, streamlined helmet, and maybe even some fresh blood)... so I doubt anybody has done Zurichsee in 1:30, ever. | |
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I was referring to Lance when I said "some people" can do it
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Nice analysis, patrick, but I think (and you know better) the physics here is more complicated than you make it seem. Consider this situation: Suppose Lance can maintain 50 kph in perfectly still air. Which means, he has enough power in his legs to overcome resistance of 50 kph
relative velocity (of course resistance is proportional to the
square of velocity).
Now suppose suddenly we have a tailwind of 75 kph. What happens then?
(a) He no longer has to cut thru' the air which he was earlier cutting thru @50 kph, so he now has abundant spare power (as we all know, mechanical friction and tire rolling resistance add up to just 10-20% of total resistance for elite cyclists. Fortunately, unlike air resistance, these two only increase linearly).
(b) the 75 kph wind is actually pushing him till he attains 75 kph. This is in addition to the effect of (a). Only after he exceeds 75 kph does he start cutting into air, and have relative velocity and wind resistance.
So, with the combined effects of (a) and (b), he ought to now achieve 125 kph? Of course my analysis is wrong, but where? Should we have another thread dedicated to this? I don't think this part has been convered in earlier threads...