In mechanics, the concept of a material point is used in cases where the size and shape of a body do not play a role in the study of its motion, but only mass is important. See what 'Material point' is in other dictionaries: In a good approximation, a monatomic molecule (inert gases, metal vapors, etc.) can sometimes be considered as a material point, but even in such molecules at a sufficiently high temperature, excitation of electron shells is observed due to collisions of molecules, followed by emission. However, this is not always the case: vibrations and rotations of a molecule are an important reservoir of the 'internal energy' of a molecule, the 'capacity' of which is determined by the size of the molecule, its structure and chemical properties. It would seem that it can be neglected and the molecule can be considered a material point. The limited application of the concept of a material point is seen from such an example: in a rarefied gas at a high temperature, the size of each molecule is very small compared to the typical distance between molecules. At the same time, the model of the motion of a body described by a material point, which consists in changing its distance from a certain instantaneous center of rotation and two Euler angles, which set the direction of the line connecting this point with the center, is extremely widely used in many branches of mechanics. This automatically means the inability of a material point to deformations (only an absolutely rigid body can be called a material point) and rotation around its own axis and changes in the direction of this axis in space. Mechanical energy can be stored by a material point only in the form of kinetic energy of its movement in space, and (or) potential energy of interaction with the field. The mass, position and speed of a material point at any given moment in time completely determine its behavior and physical properties. When straight motion body, one coordinate axis is enough to determine its position. In practice, a material point is understood as a body with mass, the size and shape of which can be neglected when solving this problem. The position of a material point in space is defined as the position of a geometric point. Material point (particle) - the simplest physical model in mechanics - an ideal body, the dimensions of which are equal to zero, the dimensions of the body can also be considered infinitely small in comparison with other dimensions or distances within the assumptions of the problem under study.

Cinematica angular formulas