but back on the theory
in 20 mins, at the same 128kmh, you have done 42.6666666 km
or 42666.666666666 metres
or 4266666.6666666 cms
divide that by the 195 odd cm circum
= 21806.715 tyre rotations.
now, miscounting this as 21807 over the 20 mins isn't going to make much difference.
miscounting the 9.086117 as 9.1 in half a second, however, will make a much bigger difference.
phew!
anyone still there?
Hello?
