There have been studies the proved that the cheetah uses its tail to change directions really fast and keep up its speed. A new paper by a pair of French physicists concludes that it’s the body length, not the mass, of the animal that determines its top speed.
As physicists have come up with a calculation that says that most animals should cover roughly ten times their body length per second at top speeds, we have some laws which are comparably with the above for the calculation of an animal’s running speed.
Take the square-cube law for instance. First described by Galileo in 1638, it states that as something gets bigger, its volume grows faster than its surface area. This law is precisely what contributes to the difficulty in building increasingly taller skyscrapers.
As Alex Klotz writes at Physics Forums, this means that as things get bigger, their own weight becomes more significant compared to their strength. (Ants can carry 50 times their own weight, squirrels can run up trees, and humans can do pull-ups.). This also applies to an object’s terminal velocity, as J.B.S. Haldane described in his classic 1926 article for Harper’s Magazine:
You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes.
Taking into consideration three important factors, the french physicists, Nicole Meyer-Vernet and Jean-Pierre Rospars, came to the following conclusion. They looked at three features they believe all the organisms they included share: first, they all have roughly the density of water (since we’re all mostly water); second, all move by contracting muscles with similar protein structure; and finally, they assume a metabolic rate of 2 kilowatts for every kilogram of muscle.
Certain other catches in this calculation have to be taken into consideration such as, the medium through which the organism is moving. Water for bacteria, is like molten asphalt for humans. The physicists have duly noted and used this finding during the calculation of bacteria speeds.
“Even if you take the fastest bacteria and compare it to the slowest whale to try and shoot down their argument, you will have to explain a -.0.06 power law instead of a 0.0 power law,” Klotz writes. “So their message stands: to zeroth-order, body traversal speed is independent of mass.”
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Author:Technology Blog
