Abslyut nol harorat

Newton's third law: the forces of interaction of two material points in the inertial reference frame are equal in magnitude and directed in opposite directions:
Gravity is the force acting on the body due to its attraction to the Earth, equal in modulus to the strength of the reaction, but directed opposite to it.
The weight of a body is the force with which the body, due to its attraction to a rotating Earth, acts on a support or suspension that keeps it from free fall.
The first cosmic speed is the velocity that must be communicated to the body so that it becomes a satellite of the Earth (or another planet, and also of the Moon or some massive celestial body) and moves along a circle whose plane passes through the center of the Earth (the Moon, etc.). ) And the center of which coincides with the center of the Earth (the Moon, etc.)
Forces of elasticity - the forces that arise during elastic deformation of bodies.
The strength of the reaction of the support (suspension) or the tension force of the suspension is the force of elasticity acting on the body considered in the given task from the side of the support or suspension.
Hooke's law for one-dimensional stretching (or compression), characterized by a vector of elongation (compression): the elastic force is proportional to the elongation (compression) vector and opposite to it in the direction:
External friction is the interaction between different contacting bodies, which prevents their relative displacement. If friction occurs between parts of the same body, then it is called internal friction.
Dry friction, the friction between the surfaces of two contiguous solids in the absence of a liquid or gaseous interlayer between them, is called dry friction. Dry friction is divided into: a) friction of rest - friction in the absence of relative displacement of contacting bodies; B) friction of sliding - friction with relative motion of contacting bodies.