Need for speed.

Here's an interesting fact (or not!) courtesy of correspondence in my paper. The title of "The World's Fastest Man" traditionally goes to the holder of the world 100m record. At present this is the Jamaican Usain Bolt, whose time of 9.72 seconds equates to a speed of just over 23 mph. But the world 200m record - currently held by the American Michael Johnson, is 19.32 seconds, which works out at 0.15 mph faster! Of course, these are average speeds - it has been pointed out that the question of which man attained the higher instantaneous speed is a different matter, and may well come down in favour of the 100m runner. So there!