Abslyut nol harorat

Viscous friction is the friction between the surface of a solid and the surrounding liquid or gaseous medium in which the body moves.
The frictional force of rest is the frictional force preventing the occurrence of the motion of one body over the surface of the other.
A spring dynamometer is a graduated spring designed to measure forces.
Statics studies the equilibrium of material points, bodies or systems of bodies.
Potential forces are called, whose work depends only on the initial and final position of the moving material point or body and does not depend on the shape of the trajectory. Forces whose work depends on the shape of the trajectory are called non-potential.
Conservative system of bodies is a system of bodies that has internal and external forces acting on the bodies of the system, potential.
Energy is a scalar physical quantity that is a single measure of the various forms of motion of matter and a measure of the transition of the motion of matter from one form to another.
The mechanical energy E characterizes the motion and interaction of bodies and is a function of the velocities and relative positions of the bodies. It is equal to the sum of the kinetic and potential energies.
A potential energy is a part of the mechanical energy, which depends on the configuration of the system, that is, on the relative position of its parts and their position in the external force field.
The impact is the phenomenon of the change in the velocities of bodies over a very small time interval of their collision. A shock is called absolutely elastic if the forces of interaction of colliding bodies are potential and as a result of interaction the mechanical energy of the system does not change. A blow is called central if the velocities of the bodies before the impact are directed along the line connecting the centers of mass of the bodies.
The second cosmic velocity is the lowest velocity that the body must be told to overcome the gravitational attraction of the Earth (or the Moon, or some other massive celestial body) away from it by an infinitely large distance: