The seven lives of a cat

A traditional saying says that cats have seven lives. That’s because they always (almost always) get up. Does science give a consistent explanation for this? The fall of the cat was present in the heads of scientists since ancient times. Galileo uses it, for example, in a letter addressed to an Aristotelian, Maxwell (XVIII), in a letter to his wife. Maxwell gives a first scientific explanation, but had an inconvenience: the human eye is unable to follow the movements of the fall of a cat. A few years later, Marey published an article with ultra -fast photos in which the cat’s movements are appreciated during his fall and gives a statement.

Marey’s photos show that the autumn movement is very complex and the laws of nature seems to be challenging. This caught the attention of physicists and during the twentieth century, countless models that describe the fall of the cat are published. None has been completed. That is why some fringes must become superfluous to solve. A warning: Like in other cases, there are explanations, not in serious scientific literature, which are incorrect. There are distribution pages that must be given care. Some indicate that in the fall a physical size that we used to describe the movement of the skater, the corner momentum, something that would lead to a paradox are stored.

The cat is a deformable body that in its fall makes a complex movement that does not violate the Angular Momentum Conservation Law. There are different models to describe the fall. The cat performs two types of movements in one of them. A curvature at the waist and the two halves of his body, on one side and one of his waist, turn in the opposite direction. The comparisons describing these movements achieve an end result in which the cat, thrown up with the legs, rotates his body 180º.

There are other details that depend on the specific type of cat (with tail, without, large, small). In this, as with many other problems in the animal world, we have to keep in mind that physicists initially seek a complex problem, the simplest solution. Nature, however, strives for the most effective solution and both solutions do not always coincide.

Robots

Models with robotics are currently made from two points of view. Some try to understand what happens in the fall and, others, the manufacture of a robot that can accurately reproduce the movements while falling. There are other models based on what geometric phases are called: they consider a cat that starts his movement with the legs up and ends up 180º. That happens in other phenomena, such as the pendulum of Foucoult or the polarized light. The maths they explain are similar.

We have a question about: is it worthwhile to spend time? In addition to the satisfaction of finding an explanation, there are the possible current or future applications of the deformable bodies. The rotation of astronauts in non -engraving conditions.