Abslyut nol harorat

Inertial frame of reference - frame of reference, in which the free material point is at rest or moves rectilinearly and uniformly.
Inertial motion is the rectilinear and uniform motion of a free material point in an inertial frame of reference.
A noninertial frame of reference is a frame of reference in which a free material point or free body does not retain the velocity of motion unchanged (non-inertial motion).
Internal forces are the forces of interaction between parts of some considered system of bodies.
External forces are the forces of action on the bodies of a given system on the part of bodies not included in this system.
A closed (isolated) system is a system of bodies, for each of which external forces do not act.
Inertia is a property of the body to maintain its speed in the absence of interaction with other bodies.
An inertial mass is a physical quantity that is a measure of the inertia of a material point or a measure of the inertness of a body in the forward motion.
Mass also characterizes another property of bodies - their ability to interact with other bodies in accordance with the law of universal gravitation. In these cases, the mass appears as a measure of gravity, or a measure of gravity, and it is called the gravitational mass.
The momentum of a material point is a vector quantity equal to the product of the mass, the point of the velocity, and its motion.
The density of the body at a given point is equal to the limit of the ratio of the mass of the element of the body chosen in the neighborhood of a given point to its volume with unlimited reduction.
Newton's second law: the acceleration acquired by a material point in the inertial frame of reference, directly proportional to the force acting on the point, is inversely proportional to the mass of the point and coincides in direction with the force:
A centripetal force is a force or a resultant of several forces, which ensures the motion of a material point (or body) along a circle.