scholarly journals A contribution to the theory of the extended Lagrangian formalism for rheonomic systems

2009 ◽  
Vol 36 (1) ◽  
pp. 47-83 ◽  
Author(s):  
Djordje Musicki
Keyword(s):  
Conservation Laws ◽  
Conservation Law ◽  
Mechanical Systems ◽  
Frame Of Reference ◽  
Horizontal Axis ◽  
Energy Change ◽  
Lagrangian Formalism ◽  
Inclined Plane ◽  
Nonconservative Systems ◽  
Generalized Coordinates

In this paper the generalization of the notion of variation in the extended Lagrangian formalism for the rheonomic mechanical systems (Dj. Musicki, 2004) is formulated and analyzed in details. This formalism is based on the extension of a set of generalized coordinates by new quantities, which determine the position of the frame of reference to which the chosen generalized coordinates refer. In the process of varying, the notion of variation is extended so that these introduced quantities, being additional generalized coordinates, must also to be varied, since the position of each particle of this system is completely determined only by all these generalized coordinates. With the consistent utilization of this notion of variation, the main results of this extended Lagrangian formalism are systematically presented, with the emphasis on the corresponding energy laws, first examined by V. Vujicic (1987), where there are two types of the energy change laws dE/dt and the corresponding conservation laws. Furthermore, the generalized Noether's theorem for the nonconservative systems with the associated Killing's equations (B. Vujanovic, 1978) is extended to this formulation of mechanics, and applied for obtaining the corresponding energy laws. It is demonstrated that these energy laws, which are more general and more natural than the usual ones, are in full accordance with the corresponding ones in the vector formulation of mechanics, if they are expressed in terms of quantities introduced in this extended Lagrangian formalism. Finally, the obtained results are illustrated by an example: the motion of a damped linear harmonious oscillator on an inclined plane, which moves along a horizontal axis, where it is demonstrated that there is valid an energy-like conservation law of Vujanovic's type.

scholarly journals Extended Lagrangian formalism for rheonomic systems with variable mass

2017 ◽  
Vol 44 (1) ◽  
pp. 115-132 ◽  
Author(s):  
Djordje Musicki
Keyword(s):  
Energy Conservation ◽  
Variable Mass ◽  
Frame Of Reference ◽  
Lagrangian Formalism ◽  
Extended System ◽  
Generalized Coordinates ◽  
Lagrangian Equations ◽  
Straight Line ◽  
The Masses ◽  
Energy Relations

In this paper the extended Lagrangian formalism for the rheonomic systems (Dj. Musicki, 2004), which began with the modification of the mechanics of such systems (V. Vujicic, 1987), is extended to the systems with variable mass, with emphasis on the corresponding energy relations. This extended Lagrangian formalism is based on the extension of the set of chosen generalized coordinates by new quantities, suggested by the form of nonstationary constraints, which determine the position of the frame of reference in respect to which these generalized coordinates refer. As a consequence, an extended system of the Lagrangian equations is formulated, accommodated to the variability of the masses of particles, where the additional ones correspond to the additional generalized coordinates. By means of these equations, the energy relations of such systems have been studied, where it is demonstrated that here there are four types of energy conservation laws. The obtained energy laws are more complete and natural than the corresponding ones in the usual Lagrangian formulation for such systems. It is demonstrated that the obtained energy laws, are in full accordance with the energy laws in the corresponding vector formulation, if they are expressed in terms of the quantities introduced in this formulation of mechanics. The obtained results are illustrated by an example: the motion of a rocket, which ejects the gasses backwards, while this rocket moves up a straight line on an oblique plane, which glides uniformly in a horizontal direction.

Proof of the no-interaction theorem without hamiltonian and lagrangian formalism

1994 ◽  
Vol 445 (1923) ◽  
pp. 221-229 ◽  
Keyword(s):  
Angular Momentum ◽  
Conservation Laws ◽  
Lagrangian Formalism ◽  
The Individual ◽  
Individual Particles

The proofs of the no-interaction theorem have been given by many authors in the framework of hamiltonian and lagrangian formalism. They are based on the assumption that there is hamiltonian or lagrangian describing the interaction between particles. This paper presents the proof without such an assumption for one, two, three and four particles. We assume the conservation laws for the linear and angular momentum that are the sums of the respective quantities of individual particles. Then there is no interaction, i. e. the worldlines of the individual particles are straight.

On conservation laws and necessary conditions in the calculus of variations

2002 ◽  
Vol 132 (6) ◽  
pp. 1361-1371 ◽  
Author(s):  
G. Francfort ◽  
J. Sivaloganathan
Keyword(s):  
Conservation Laws ◽  
Calculus Of Variations ◽  
Conservation Law ◽  
Necessary Conditions ◽  
Lagrange Equation ◽  
Integral Functional ◽  
Variational Symmetry

It is well known from the work of Noether that every variational symmetry of an integral functional gives rise to a corresponding conservation law. In this paper, we prove that each such conservation law arises directly as the Euler-Lagrange equation for the functional on taking suitable variations around a minimizer.

On the symmetry and conservation law classification of the de Sitter–Schwarzschild metric and the corresponding wave and Klein–Gordon equations

2020 ◽  
Vol 17 (11) ◽  
pp. 2050172
Author(s):  
Ashfaque H. Bokhari ◽  
A. H. Kara ◽  
F. D. Zaman ◽  
B. B. I. Gadjagboui
Keyword(s):  
Conservation Laws ◽  
Conservation Law ◽  
De Sitter ◽  
Killing Vectors ◽  
Schwarzschild Geometry ◽  
Klein Gordon ◽  
Spacetime Metric ◽  
Variational Symmetries ◽  
Symmetry And Conservation Law

The main purpose of this work is to focus on a discussion of Lie symmetries admitted by de Sitter–Schwarzschild spacetime metric, and the corresponding wave or Klein–Gordon equations constructed in the de Sitter–Schwarzschild geometry. The obtained symmetries are classified and the variational (Noether) conservation laws associated with these symmetries via the natural Lagrangians are obtained. In the case of the metric, we obtain additional variational ones when compared with the Killing vectors leading to additional conservation laws and for the wave and Klein–Gordon equations, the variational symmetries involve less tedious calculations as far as invariance studies are concerned.

scholarly journals Stability of the 1D IBVP for a non autonomous scalar conservation law

2018 ◽  
Vol 149 (03) ◽  
pp. 561-592 ◽  
Author(s):  
Rinaldo M. Colombo ◽  
Elena Rossi
Keyword(s):  
Conservation Laws ◽  
Boundary Value Problems ◽  
Conservation Law ◽  
Space Dimension ◽  
Initial Boundary ◽  
Initial Boundary Value Problems ◽  
Scalar Conservation Law ◽  
Scalar Conservation ◽  
The Stability ◽  
Initial Boundary Value

We prove the stability with respect to the flux of solutions to initial – boundary value problems for scalar non autonomous conservation laws in one space dimension. Key estimates are obtained through a careful construction of the solutions.

scholarly journals Symmetries, pseudosymmetries and conservation laws in Lagrangian and Hamiltonian k-symplectic formalisms

2016 ◽  
Vol 13 (03) ◽  
pp. 1650026
Author(s):  
Florian Munteanu
Keyword(s):  
Conservation Laws ◽  
Hamiltonian Systems ◽  
Conservation Law ◽  
Type Theorem ◽  
Natural Extension ◽  
Lagrangian Systems ◽  
Symmetry And Conservation Law

In this paper, we will present Lagrangian and Hamiltonian [Formula: see text]-symplectic formalisms, we will recall the notions of symmetry and conservation law and we will define the notion of pseudosymmetry as a natural extension of symmetry. Using symmetries and pseudosymmetries, without the help of a Noether type theorem, we will obtain new kinds of conservation laws for [Formula: see text]-symplectic Hamiltonian systems and [Formula: see text]-symplectic Lagrangian systems.

Underactuated Mechanical Systems from the Lagrangian Formalism

2014 ◽  
pp. 15-33
Author(s):  
Amal Choukchou-Braham ◽  
Brahim Cherki ◽  
Mohamed Djemaï ◽  
Krishna Busawon
Keyword(s):  
Mechanical Systems ◽  
Lagrangian Formalism ◽  
Underactuated Mechanical Systems

scholarly journals On the Generation of Infinitely Many Conservation Laws of the Black-Scholes Equation

Computation ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 65
Author(s):  
Winter Sinkala
Keyword(s):  
Differential Equations ◽  
Conservation Laws ◽  
Conservation Law ◽  
The Other ◽  
Multiplier Method ◽  
Lie Point Symmetries ◽  
Mathematical Study ◽  
Black Scholes

Construction of conservation laws of differential equations is an essential part of the mathematical study of differential equations. In this paper we derive, using two approaches, general formulas for finding conservation laws of the Black-Scholes equation. In one approach, we exploit nonlinear self-adjointness and Lie point symmetries of the equation, while in the other approach we use the multiplier method. We present illustrative examples and also show how every solution of the Black-Scholes equation leads to a conservation law of the same equation.

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