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Mechanical system of material points or bodies is such a set of them in which the position and movement of each point (or body) depends on the position and movement of the others.
A material body is considered as a system of material points (particles) that form this body.
Outside forces called such forces that act on points or bodies of a mechanical system from points or bodies that do not belong to this system.
internal forces, are called such forces that act on points or bodies of a mechanical system from points or bodies of the same system, i.e. with which the points or bodies of a given system interact with each other.
External and internal forces of the system, in turn, can be active and reactive.
System weight equals the algebraic sum of the masses of all points or bodies of the system In a uniform gravitational field, for which, the weight of any particle of the body is proportional to its mass. Therefore, the distribution of masses in the body can be determined by the position of its center of gravity - a geometric point FROM, whose coordinates are called the center of mass or the center of inertia of the mechanical system
Theorem on the motion of the center of mass of a mechanical system: the center of mass of a mechanical system moves as a material point, the mass of which is equal to the mass of the system, and to which all external forces acting on the system are applied
Conclusions:
- A mechanical system or a rigid body can be considered as a material point, depending on the nature of its motion, and not on its size.
- Internal forces are not taken into account by the theorem on the motion of the center of mass.
- The theorem on the motion of the center of mass does not characterize the rotational motion of a mechanical system, but only translational
The law of conservation of motion of the center of mass of the system:
1. If the sum of external forces (the main vector) is constantly equal to zero, then the center of mass of the mechanical system is at rest or moves uniformly and rectilinearly.
2. If the sum of the projections of all external forces on any axis is equal to zero, then the projection of the velocity of the center of mass of the system on the same axis is a constant value.
Theorem on the change in momentum.
The amount of movement of a material point and - a vector quantity, which is equal to the product of the mass of the point and the vector of its velocity.
The unit of measure for momentum is (kg m/s).
Quantity of movement of the mechanical system- a vector quantity equal to the geometric sum (main vector) of the momentum of all points of the system. Or the momentum of the system is equal to the product of the mass of the entire system and the speed of its center of mass
When a body (or system) moves in such a way that its center of mass is stationary, then the momentum of the body is zero (for example, the rotation of the body around a fixed axis that passes through the center of mass of the body).
If the motion of the body is complex, then it will not characterize the rotational part of the motion when rotating around the center of mass. That is, the amount of motion characterizes only the translational motion of the system (together with the center of mass).
Impulse of force characterizes the action of a force over a certain period of time.
The impulse of force over a finite period of time is defined as the integral sum of the corresponding elementary impulses
Theorem on the change in momentum of a material point:
(in differential form): The derivative over time of the momentum of a material point is equal to the geometric sum of the forces acting on the points
(in integral form): The change in momentum over a period of time is equal to the geometric sum of the impulses of forces applied to a point over the same period of time.
Theorem on the change in the momentum of a mechanical system
(in differential form): The time derivative of the momentum of the system is equal to the geometric sum of all external forces acting on the system.
(in integral form): The change in the momentum of the system over a certain period of time is equal to the geometric sum of the impulses acting on the system of external forces over the same period of time.
The theorem makes it possible to exclude obviously unknown internal forces from consideration.
The theorem on the change in momentum of a mechanical system and the theorem on the motion of the center of mass are two different forms of the same theorem.
Law of conservation of momentum of the system.
- If the sum of all external forces acting on the system is equal to zero, then the momentum vector of the system will be constant in direction and modulo.
- If the sum of the projections of all acting external forces on any arbitrary axis is equal to zero, then the projection of the momentum on this axis is a constant value.
Conservation laws indicate that internal forces cannot change the total momentum of the system.
- Classification of forces acting on a mechanical system
- Properties of internal forces
- Mass of the system. Center of mass
- Differential equations of motion of a mechanical system
- Theorem on the motion of the center of mass of a mechanical system
- Law of conservation of motion of the center of mass of the system
- Theorem on the change in momentum
- Law of conservation of momentum of the system
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An example of the calculation of a spur gear
An example of the calculation of a spur gear. The choice of material, the calculation of allowable stresses, the calculation of contact and bending strength were carried out.
An example of solving the problem of beam bending
In the example, diagrams of transverse forces and bending moments are plotted, a dangerous section is found, and an I-beam is selected. In the problem, the construction of diagrams using differential dependencies was analyzed, a comparative analysis of various beam cross sections was carried out.
An example of solving the problem of shaft torsion
The task is to test the strength of a steel shaft for a given diameter, material and allowable stresses. During the solution, diagrams of torques, shear stresses and twist angles are built. Self weight of the shaft is not taken into account
An example of solving the problem of tension-compression of a rod
The task is to test the strength of a steel rod at given allowable stresses. During the solution, plots of longitudinal forces, normal stresses and displacements are built. Self weight of the bar is not taken into account
Application of the kinetic energy conservation theorem
An example of solving the problem of applying the theorem on the conservation of kinetic energy of a mechanical system
Determination of the speed and acceleration of a point according to the given equations of motion
An example of solving the problem of determining the speed and acceleration of a point according to the given equations of motion
Determination of velocities and accelerations of points of a rigid body during plane-parallel motion
An example of solving the problem of determining the velocities and accelerations of points of a rigid body during plane-parallel motion
The system referred to in the theorem can be any mechanical system consisting of any bodies.
Statement of the theorem
The amount of motion (momentum) of a mechanical system is a value equal to the sum of the quantities of motion (momentum) of all bodies included in the system. The impulse of external forces acting on the bodies of the system is the sum of the impulses of all external forces acting on the bodies of the system.
( kg m/s)
The theorem on the change in the momentum of the system states
The change in the momentum of the system over a certain period of time is equal to the impulse of external forces acting on the system over the same period of time.
Law of conservation of momentum of the system
If the sum of all external forces acting on the system is equal to zero, then the momentum (momentum) of the system is a constant value.
,
we obtain the expression of the theorem on the change in the momentum of the system in differential form:
Having integrated both parts of the resulting equality over an arbitrarily taken time interval between some and , we obtain the expression of the theorem on the change in the momentum of the system in integral form:
Law of conservation of momentum (Law of conservation of momentum) states that the vector sum of the impulses of all bodies of the system is a constant value if the vector sum of the external forces acting on the system is equal to zero.
(Moment of momentum m 2 kg s −1)
Theorem on the change in the angular momentum about the center
the time derivative of the moment of momentum (kinetic moment) of a material point relative to any fixed center is equal to the moment of the force acting on the point relative to the same center.
dk 0 /dt = M 0 (F ) .
Theorem on the change in the angular momentum about the axis
the time derivative of the moment of momentum (kinetic moment) of a material point with respect to any fixed axis is equal to the moment of the force acting on this point with respect to the same axis.
dk x /dt = M x (F ); dk y /dt = M y (F ); dk z /dt = M z (F ) .
Consider a material point M weight m moving under the influence of a force F (Figure 3.1). Let's write down and construct the vector of the angular momentum (kinetic momentum) M 0 material point relative to the center O :
Differentiate the expression for moment of momentum (kinetic moment k 0) by time:
Because dr /dt = V , then the vector product V ⊗ m ⋅ V (collinear vectors V and m ⋅ V ) is zero. In the same time d(m ⋅ v) /dt = F according to the theorem on the momentum of a material point. Therefore, we get that
dk 0 /dt = r ⊗F , (3.3)
where r ⊗F = M 0 (F ) – vector-moment of force F relative to the fixed center O . Vector k 0 ⊥ plane ( r , m ⊗V ), and the vector M 0 (F ) ⊥ plane ( r ,F ), we finally have
dk 0 /dt = M 0 (F ) . (3.4)
Equation (3.4) expresses the theorem on the change in the angular momentum (kinetic moment) of a material point relative to the center: the time derivative of the moment of momentum (kinetic moment) of a material point relative to any fixed center is equal to the moment of the force acting on the point relative to the same center.
Projecting equality (3.4) onto the axes of Cartesian coordinates, we obtain
dk x /dt = M x (F ); dk y /dt = M y (F ); dk z /dt = M z (F ) . (3.5)
Equalities (3.5) express the theorem on the change in the angular momentum (kinetic momentum) of a material point about the axis: the time derivative of the moment of momentum (kinetic moment) of a material point with respect to any fixed axis is equal to the moment of the force acting on this point with respect to the same axis.
Let us consider the consequences following from theorems (3.4) and (3.5).
Consequence 1. Consider the case when the force F during the entire movement of the point passes through the fixed center O (case of central force), i.e. when M 0 (F ) = 0. Then it follows from Theorem (3.4) that k 0 = const ,
those. in the case of a central force, the moment of momentum (kinetic moment) of a material point relative to the center of this force remains constant in magnitude and direction (Figure 3.2).
Figure 3.2
From the condition k 0 = const it follows that the trajectory of the moving point is a plane curve, the plane of which passes through the center of this force.
Consequence 2. Let M z (F ) = 0, i.e. force crosses the axis z or parallel to it. In this case, as can be seen from the third of equations (3.5), k z = const ,
those. if the moment of the force acting on a point relative to any fixed axis is always equal to zero, then the angular momentum (kinetic moment) of the point relative to this axis remains constant.
Proof of the momentum change theorem
Let the system consist of material points with masses and accelerations . All forces acting on the bodies of the system can be divided into two types:
External forces - forces acting from bodies that are not included in the system under consideration. The resultant of external forces acting on a material point with the number i denote .
Internal forces are the forces with which the bodies of the system itself interact with each other. The force with which the point with the number i point number is valid k, we will denote , and the impact force i-th point on k-th point - . Obviously, for , then
Using the introduced notation, we write Newton's second law for each of the considered material points in the form
Given that 
and summing up all the equations of Newton's second law, we get:
The expression is the sum of all internal forces acting in the system. According to Newton's third law, in this sum, each force corresponds to a force such that and, therefore, is fulfilled 
Since the whole sum consists of such pairs, the sum itself is equal to zero. Thus, one can write
Using the designation for the momentum of the system, we obtain
Introducing into consideration the change in the momentum of external forces 
, we obtain the expression of the theorem on the change in the momentum of the system in differential form:
Thus, each of the last obtained equations allows us to assert: the change in the momentum of the system occurs only as a result of the action of external forces, and internal forces cannot have any effect on this value.
Having integrated both parts of the obtained equality over an arbitrarily taken time interval between some and , we obtain the expression of the theorem on the change in the momentum of the system in integral form:
where and are the values of the amount of motion of the system at the moments of time and, respectively, and is the impulse of external forces over a period of time . In accordance with the above and the introduced notation,
and mechanical system
The amount of motion of a material point is a vector measure of mechanical movement, equal to the product of the mass of the point and its speed, . The unit of measurement of the amount of motion in the SI system is 
. The amount of movement of a mechanical system is equal to the sum of the amounts of movements of all material points that form the system:
.
(5.2)
We transform the resulting formula
.
According to formula (4.2) 
, that's why
.
Thus, the momentum of a mechanical system is equal to the product of its mass and the velocity of the center of mass:
.
(5.3)
Since the amount of motion of the system is determined by the motion of only one of its points (the center of mass), it cannot be a complete characteristic of the motion of the system. Indeed, for any movement of the system, when its center of mass remains stationary, the momentum of the system is equal to zero. For example, this occurs when a rigid body rotates around a fixed axis passing through its center of mass.
We introduce a reference system Cxyz, which originates at the center of mass of the mechanical system FROM and moving forward relative to the inertial system 
(Fig. 5.1). Then the movement of each point 
can be considered as complex: translational movement along with axes Cxyz and movement about these axes. Due to the translational movement of the axes Cxyz the portable speed of each point is equal to the speed of the center of mass of the system, and the momentum of the system, determined by formula (5.3), characterizes only its translational translational motion.
5.3. Impulse of force
To characterize the action of a force over a certain period of time, a quantity called momentum of force . The elementary impulse of a force is a vector measure of the action of a force, equal to the product of the force and the elementary time interval of its action:
.
(5.4)
The unit of measurement of the impulse of force in the SI system is 
, i.e. the dimensions of the momentum of force and momentum are the same.
Impulse of force over a finite period of time 
is equal to a certain integral of the elementary momentum:
.
(5.5)
The impulse of a constant force is equal to the product of the force and the time of its action:
.
(5.6)
In the general case, the momentum of a force can be determined by its projections onto the coordinate axes:
.
(5.7)
5.4. Theorem on the change in momentum
material point
In the main equation of dynamics (1.2), the mass of a material point is a constant value, its acceleration 
, which makes it possible to write this equation in the form:
.
(5.8)
The resulting relation allows us to formulate theorem on the change in momentum of a material point in differential form: The time derivative of the momentum of a material point is equal to the geometric sum (principal vector) of the forces acting on the point.
We now obtain the integral form of this theorem. It follows from relation (5.8) that
.
Let us integrate both parts of the equality within the limits corresponding to the moments of time 
and 
,
.
(5.9)
The integrals on the right side are the impulses of the forces acting on the point, so after integrating the left side we get
.
(5.10)
Thus, it has been proven theorem on the change in momentum of a material point in integral form: The change in the amount of motion of a material point for a certain period of time is equal to the geometric sum of the impulses acting on the point of forces for the same period of time.
The vector equation (5.10) corresponds to a system of three equations in projections onto the coordinate axes:
;
;
(5.11)
.
Example 1
The body moves forward along an inclined plane forming an angle α with the horizon. At the initial moment of time, it had a speed 
, directed upward along the inclined plane (Fig. 5.2).
After what time will the body's velocity become equal to zero if the coefficient of friction is f ?
Let us take a progressively moving body as a material point and consider the forces acting on it. It's gravity 
, the normal response of the plane 
and friction force 
. Let's direct the axis x along the inclined plane upwards and write down the 1st equation of the system (5.11)
where are the projections of the quantities of motion and are the projections of the impulses of constant forces 
,
and 
are equal to the products of the projections of forces and the time of motion:
Since the acceleration of the body is directed along the inclined plane, the sum of the projections onto the axis y of all forces acting on the body is equal to zero: 
, whence it follows that 
. Find the force of friction
and from equation (5.12) we get
from which we determine the time of motion of the body
.
- 1. Algebraic moment of momentum about the center. Algebraic O-- scalar value, taken with a sign (+) or (-) and equal to the product of the modulus of momentum m at a distance h(perpendicular) from this center to the line along which the vector is directed m:
- 2. Vector angular momentum relative to the center.
Vector angular momentum of a material point relative to some center O -- a vector applied at this center and directed perpendicular to the plane of the vectors m and in the direction from which the movement of the point can be seen counterclockwise. This definition satisfies the vector equality
moment of momentum material point about some axis z is called a scalar value taken with a sign (+) or (-) and equal to the product of the modulus vector projections amount of motion to a plane perpendicular to this axis, to a perpendicular h, lowered from the point of intersection of the axis with the plane to the line along which the indicated projection is directed:
Momentum of a mechanical system about the center and axis
1. Kinetic moment relative to the center.
momentum or the main moment of the momentum of the mechanical system with respect to some center is called the geometric sum of the moments of the quantities of motion of all material points of the system relative to the same center.
2. Kinetic moment about the axis.
The angular momentum or the main moment of the momentum of a mechanical system relative to some axis is the algebraic sum of the momentum of the momentum of all material points of the system relative to the same axis.
3. Momentum of a rigid body rotating around a fixed axis z with angular velocity.
Theorem on the change in the angular momentum of a material point relative to the center and axis
1. Theorem of moments with respect to the center.
Derivative in time from the moment of momentum of a material point relative to some fixed center is equal to the moment of force acting on the point relative to the same center
2. The theorem of moments about the axis.
Derivative in time from the moment of momentum of a material point relative to some axis is equal to the moment of force acting on the point, relative to the same axis
Theorem on the change in the kinetic moment of a mechanical system relative to the center and axis
Theorem of moments about the center.
Derivative in time from the angular momentum of a mechanical system relative to some fixed center is equal to the geometric sum of the moments of all external forces acting on the system relative to the same center;
Consequence. If the main moment of external forces relative to a certain center is equal to zero, then the angular momentum of the system relative to this center does not change (the law of conservation of angular momentum).
2. The theorem of moments about the axis.
Derivative in time from the angular momentum of a mechanical system relative to some fixed axis is equal to the sum of the moments of all external forces acting on the system relative to this axis
Consequence. If the main moment of external forces about some axis is equal to zero, then the kinetic moment of the system about this axis does not change.
For example = 0, then L z = const.
Work and power of forces
Force work is a scalar measure of the action of a force.
1. Elementary work of force.
Elementary the work of a force is an infinitesimal scalar quantity equal to the scalar product of the force vector and the infinitesimal displacement vector of the force application point: ; - radius-vector increment force application point, the hodograph of which is the trajectory of this point. Elementary displacement points along the path coincides with due to their smallness. That's why
if then dA > 0;if, then dA = 0;if , then dA< 0.
2. Analytic expression for elementary work.
Imagine vectors and d through their projections on the axes of Cartesian coordinates:
, . Get (4.40)
3. The work of the force on the final displacement is equal to the integral sum of the elementary works on this displacement
If the force is constant and the point of its application moves in a straight line,
4. The work of gravity. We use the formula: Fx = Fy = 0; Fz=-G=-mg;
where h- moving the point of application of force vertically down (height).
When moving the point of application of gravity upward A 12 = -mgh(dot M 1 -- at the bottom, M 2 - above).
So, . The work of gravity does not depend on the shape of the trajectory. When moving along a closed path ( M 2 is the same as M 1 ) work is zero.
5. The work of the elastic force of the spring.
The spring stretches only along the axis X:
F y = F z = O, F x = = -sh;
where is the value of the spring deformation.
When moving the point of application of force from the lower position to the upper position, the direction of force and the direction of movement are the same, then
Therefore, the work of the elastic force
The work of forces on the final displacement; If = const, then
where is the final angle of rotation; , where P -- the number of revolutions of the body around the axis.
Kinetic energy of a material point and a mechanical system. König's theorem
Kinetic energy is a scalar measure of mechanical motion.
Kinetic energy of a material point - a scalar positive value equal to half the product of the mass of a point and the square of its speed,
Kinetic energy of a mechanical system -- the arithmetic sum of the kinetic energies of all material points of this system:
The kinetic energy of a system consisting of P interconnected bodies is equal to the arithmetic sum of the kinetic energies of all bodies of this system:
König's theorem
Kinetic energy of a mechanical system in the general case of its motion is equal to the sum of the kinetic energy of the system motion together with the center of mass and the kinetic energy of the system as it moves relative to the center of mass:
where Vkc- speed k- th points of the system relative to the center of mass.
Kinetic energy of a rigid body in various motions
Progressive movement.
Rotation of a body around a fixed axis . ,where -- the moment of inertia of the body about the axis of rotation.
3. Plane-parallel motion. , where is the moment of inertia of a flat figure about an axis passing through the center of mass.
With flat motion body kinetic energy is the sum of the kinetic energy of the translational motion of the body with the speed of the center of mass and kinetic energy of rotational motion around an axis passing through the center of mass, ;
Theorem on the change in the kinetic energy of a material point
Theorem in differential form.
Differential from the kinetic energy of a material point is equal to the elementary work of the force acting on the point,
Theorem in integral (finite) form.
Change The kinetic energy of a material point at some displacement is equal to the work of the force acting on the point at the same displacement.
Theorem on the change in the kinetic energy of a mechanical system
Theorem in differential form.
Differential from the kinetic energy of a mechanical system is equal to the sum of the elementary work of external and internal forces acting on the system.
Theorem in integral (finite) form.
Change The kinetic energy of a mechanical system at some displacement is equal to the sum of the work of external and internal forces applied to the system at the same displacement. ; For a system of rigid bodies = 0 (according to the property of internal forces). Then
The law of conservation of mechanical energy of a material point and a mechanical system
If the material If a point or a mechanical system is acted upon only by conservative forces, then in any position of the point or system the sum of the kinetic and potential energies remains constant.
For material point
For mechanical system T+ P= const
where T+ P -- total mechanical energy of the system.
Rigid Body Dynamics
Differential equations of motion of a rigid body
These equations can be obtained from the general theorems of the dynamics of a mechanical system.
1. The equations of the translational motion of a body - from the theorem on the motion of the center of mass of a mechanical system In projections onto the axes of Cartesian coordinates
2. The equation of rotation of a rigid body around a fixed axis - from the theorem on the change in the kinetic moment of a mechanical system relative to an axis, for example, relative to an axis
Since the kinetic moment L z rigid body about the axis, then if
Since or, then the equation can be written in the form or, the form of the equation depends on what should be determined in a particular problem.
Differential Equations of a Plane-Parallel rigid body motions are a set of equations progressive motion of a flat figure together with the center of mass and rotational movement about an axis passing through the center of mass:
physical pendulum
physical pendulum called a rigid body rotating around a horizontal axis that does not pass through the center of mass of the body, and moving under the influence of gravity.
Differential equation of rotation
In the case of small fluctuations.
Then where
Solution of this homogeneous equation.
Let at t=0 Then
-- equation of harmonic oscillations.
Period of pendulum oscillation
Reduced length a physical pendulum is the length of such a mathematical pendulum, the period of oscillation of which is equal to the period of oscillation of the physical pendulum.
Number of movement a measure of mechanical motion, equal for a material point to the product of its mass m for speed v. K. l. mv- vector quantity, directed in the same way as the velocity of a point. Sometimes K. d. is also called an impulse. Under the action of a force, the coefficient of magnitude of a point generally changes both numerically and in direction; this change is determined by the second (basic) law of dynamics (see Newton's laws of mechanics). K. d. Q of a mechanical system is equal to the geometric sum of K. d. of all its points or the product of the mass M whole system at speed vc its center of mass: Q= ∑m k v k =Mv s. The change in the coefficient of change of a system occurs under the influence of only external forces, that is, forces acting on the system from bodies that are not part of this system. According to the theorem on the change of K. d. Q 1 -Q 0 = ∑S k e . where Q 0 and Q 1 - K. d. of the system at the beginning and at the end of a certain period of time, S k e - impulses of external forces F k e (see Impulse of force) for this period of time (in differential form, the theorem is expressed by the Dynamics equation) ,
in particular in the theory of Impact a.
For a closed system, i.e., a system that does not experience external influences, or in the case when the geometric sum of external forces acting on the system is equal to zero, the conservation law of the K. d. under the action of internal forces) can change, but in such a way that the value Q = ∑m to v k remains constant. This law explains such phenomena as jet propulsion, recoil (or recoil) when fired, the operation of a propeller or oars, etc. For example, if we consider a gun and a bullet as one system, then the pressure of powder gases during firing will be an internal and cannot change the K. d. of the system, equal to zero before the shot. Therefore, informing the bullet K. d. m 1 v 1 , directed towards the muzzle, the powder gases will simultaneously report to the gun numerically the same, but oppositely directed K. d. m 2 v 2 , what will cause a return; from equality m 1 v 1 = m 2 v 2(where v 1 , v 2 - numerical values of the speeds) is possible, knowing the speed v 1 ; bullets leaving the barrel, find the maximum speed v2 recoil (and for the gun - recoil). At velocities close to the speed of light c, the cd, or momentum, of a free particle is determined by the formula p = mv/β=v/c; when vc, this formula changes to the usual one: p = mv(see Relativity theory).
Physical fields also possess
(electromagnetic, gravitational, etc.). The KD of a field is characterized by the KD density (the ratio of the KD of an elementary volume to this volume) and is expressed in terms of the field strength or its potential, and so on. S. M. Targ.
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
See what the "Number of movement" is in other dictionaries:
A measure of mechanical motion, equal for a material point to the product of its mass m and speed v. The momentum mv is a vector quantity directed in the same way as the speed of a point. The momentum is also called momentum... Big Encyclopedic Dictionary
- (impulse), measure of mechanical motion, equal for a material point to the product of its mass m and the speed v. K. d. mv is a vector quantity, directed in the same way as the speed of a point. Under the action of a force, the K. d. point changes in the general case both numerically and ... ... Physical Encyclopedia
See Impulse. Philosophical encyclopedic dictionary. 2010 ... Philosophical Encyclopedia
amount of movement- impulse - [Ya.N. Luginsky, M.S. Fezi Zhilinskaya, Yu.S. Kabirov. English Russian Dictionary of Electrical Engineering and Power Industry, Moscow, 1999] Topics of electrical engineering, basic concepts Synonyms momentum EN momentumlinear momentum ... Technical Translator's Handbook
A measure of mechanical motion, equal for a material point to the product of its mass m and speed v. The amount of motion mv is a vector quantity, coinciding in direction with the velocity vector v. The momentum is also called momentum. * * *… … encyclopedic Dictionary
Impulse (momentum) is an additive integral of the motion of a mechanical system; the corresponding conservation law is related to the fundamental symmetry of the homogeneity of space. Contents 1 The history of the term 2 "School" definition ... ... Wikipedia
amount of movement- judesio kiekis statusas T sritis Standartizacija ir metrologija apibrėžtis Dydis, išreiškiamas kūno masės ir jo judėjimo greičio sandauga. atitikmenys: engl. kinetic moment; kinetic momentum; linear momentum; quantity of motion vok.… … Penkiakalbis aiskinamasis metrologijos terminų žodynas
amount of movement- judesio kiekis statusas T sritis fizika atitikmenys: angl. kinetic momentum; momentum; quantity of motion vok. Bewegungsgröße, f; Impuls, m rus. impulse, m; amount of movement, n pranc. impulse, f; quantite de mouvement, f … Fizikos terminų žodynas
Number of movement- the same as the impulse is a measure of mechanical movement, equal to the product of the mass of the body m and its speed v. The momentum vector coincides in direction with the velocity vector ... Beginnings of modern natural science
Mechanical measure. motion, equal for a material point to the product of its mass from to the speed v. K. d. mv is a vector quantity, coinciding in direction with the velocity vector v. K. d. Also impulse... Natural science. encyclopedic Dictionary
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