LIGHTNING BOLT BEATS A BULLET
HE may not be quite as fast as a speeding bullet, but Usain Bolt certainly produces more energy than one. Physicists have calculated that the world’s fastest man produced 50 times more energy during his record-breaking 100m sprint than a bullet as it leaves the barrel of a 0.44 calibre Magnum handgun.
They worked out that the runner achieved a top speed of 43km/h during his 9.58 second sprint at the 2009 World
Championships in Berlin.
Despite the explosive force produced by his muscles, the wind drag created by his 1.95m frame limited how fast he could go. They calculated that less than 8% of the mechanical energy he produced was used for movement while the rest was spent fighting the drag.
Jorge Hernandez Gomez, the lead author of the study from the National Autonomous University of Mexico, said: “It is hard to break records nowadays, even by hundredths of a second, as the runners must act powerfully against a tremendous force which increases massively with each bit of additional speed they are able to develop.
“This is because of the ‘physical barrier’ imposed by the conditions on Earth. If Bolt were to run on a planet with a less dense atmosphere, he could achieve records of fantastic proportions.”
The researchers, whose findings are published in the European Journal of Physics, calculated that Bolt produced 81.58 kilojoules of kinetic energy during the race. — ©