Moment of an impulse: features of the mechanics of a solid

The momentum moment refers to the fundamental, fundamental laws of nature. It is directly related to the symmetry properties of the space of the physical world in which we all live. Due to the law of its conservation, the moment of the impulse determines the physical laws of the movement of material bodies in space that are habitual for us. This quantity is characterized by the amount of translational or rotational motion.

The moment of the pulse, also called "kinetic", "angular" and "orbital", is an important characteristic, depending on the mass of the material body, the features of its distribution relative to the imaginary axis of revolution and the speed of movement. Here it should be clarified that in mechanics rotation has a broader interpretation. Even rectilinear motion past some arbitrarily lying point in space can be considered rotational, taking it as an imaginary axis.

The moment of the pulse and the laws of its conservation were formulated by Rene Descartes as applied to the translationally moving system of material points. True, he did not mention the conservation of rotational motion . Only a century later, Leonard Euler, and then other Swiss scientist, physicist and mathematician Daniel Bernoulli, when studying the rotation of the material system around a fixed central axis, concluded that this law also acts for this kind of displacement in space.

Further studies fully confirmed that, in the absence of an external effect, the sum of the product of the mass of all points by the total velocity of the system and the distance to the center of rotation remains unchanged. Somewhat later, the French scientist Patrick Darcy, these terms were expressed through areas swept out by the radius vectors of elementary particles over the same period of time. This made it possible to relate the moment of the impulse of the material point to certain known postulates of celestial mechanics and, in particular, to the most important position about the motion of Johannes Kepler's planets .

The angular momentum of a solid is the third dynamic variable, to which the provisions of the fundamental conservation law apply. It states that regardless of the nature and type of movement in the absence of external influence, this quantity in an isolated material system will always remain unchanged. This physical indicator can undergo any changes only if there is a nonzero moment of the acting forces.

From this law it also follows that if M = 0, any change in the distance between the body (the system of material points) and the central axis of rotation will inevitably cause an increase or decrease in the speed of its circulation around the center. For example, a gymnast performing a somersault in order to produce several revolutions in the air, initially rolls her body into a tangle. And ballerinas or figure skaters, spinning in pirouettes, spread their hands to the sides, if they want to slow down the movement, and, conversely, press them to the body when they try to whirl faster. Thus, in the sport and art fundamental laws of nature are used.