In a strict sense, the classical Newtonian mechanics and the Maxwell s theory of electromagnetism are not compatible. The M-M-type experiments refuted the geometric optics completed by classical mechanics. In classical mechanics the inertial system was a basic concept, and the equation of motion must be invariant to the Galilean transformation Eq. (1). After the M-M experiments, Eq. (1) and so any equations of motion became invalid. Einstein realized that only the Maxwell equations are invariant for the Lorentz transformation. Therefore he believed that they are the authentic equations of motion, and so he created new concepts for the space, time, inertia, and so on. Within [Pg.398]

EXAMPLE 5.1 According to classical mechanics Newtonian mechanics) particle falling vertically in a vacuum near the surface of the earth has a position given by [Pg.123]

Classical mechanics is primarily the study of the consequences of these laws. It is sometimes called Newtonian mechanics. The first law is just a special case of the second, and the third law is primarily used to obtain forces for the second law, so Newton s second law is the most important equation of classical mechanics. [Pg.237]

In classical mechanics it is proved that an observer who experiments only within a closed system cannot determine whether this system is at rest or is in uniform motion. In fact, the Newtonian equations of motion md xjdt = F (where m is the mass, F the force, X the co-ordinate of a particle, and t the time) remain unchanged if we pass to a moving co-ordinate system by the transformation a == a — vt, provided the force depends only on the position of the particle relative to the co-ordinate system (since [Pg.269]

For large molecular aggregates only classical mechanics can be applied to describe the nuclear motion of the particles through Newtonian-type equations of motion. This is an approximation, which may only fail if the motion of light particles such as protons needs to be accurately described. If the latter is the case, explicit nuclear quantum dynamics is required. Such extensions that include quantum effects [99, 100] or that incorporate full quantum dynamics have been explored [101], [Pg.433]

The method of defining complexions depends on whether we are treating our systems by classical, Newtonian mechanics or by quantum theory. First we shall take up classical mechanics, for that is more familiar. But later, when we describe the methods of quantum theory, we shall observe that that theory is more correct and more fundamental for statistical purposes. In classical mechanics, a system is, df scrihpd by tV [Pg.36]

For small values of /3 (Eq. 3.3)—that is, for small speeds—the equations of relativity reduce to the equations of Newtonian (classical) mechanics. In classical mechanics, the mass is constant, and T and p are given by [Pg.81]

It is possible to formulate the classical laws of motion in several ways. Newton s equations are taught in every basic course of classical mechanics. However, especially in the presence of constraint forces, the equations of motion can often be presented in a simpler form by using either Lagrangian or Hamiltonian formalism. In short, in the Newtonian approach, an /V-point particle system is described by specifying the position xa = xa(t) of each particle a as a function of time. The positions are found by solving the equations of motion, [Pg.272]

At the outset it is important to recognize that several mathematical frameworks for the description of dynamic systems are in common use. In this context classical mechanics can be divided into three disciplines denoted by Newtonian mechanics, Lagrangian mechanics and Hamiltonian mechanics reflecting three conceptually different mathematical apparatus of model formulation [35, 52, 2, 61, 38, 95, 60, 4], [Pg.194]

In the mixed quantum-classical molecular dynamics (QCMD) model (see [11, 9, 2, 3, 5] and references therein), most atoms are described by classical mechanics, but an important small portion of the system by quantum mechanics. The full quantum system is first separated via a tensor product ansatz. The evolution of each part is then modeled either classically or quan-tally. This leads to a coupled system of Newtonian and Schrbdinger equations. [Pg.426]

Newton s equations of motion, stated as force equals mass times acceleration , are strictly true only for mass points in Cartesian coordinates. Many problems of classical mechanics, such as the rotation of a solid, cannot easily be described in such terms. Lagrange extended Newtonian mechanics to an essentially complete nonrelativistic theory by introducing generalized coordinates q and generalized forces Q such that the work done in a dynamical process is Qkdqk [436], Since [Pg.11]

Basically, Newtonian mechanics worked well for problems involving terrestrial and even celestial bodies, providing rational and quantifiable relationships between mass, velocity, acceleration, and force. However, in the realm of optics and electricity, numerous observations seemed to defy Newtonian laws. Phenomena such as diffraction and interference could only be explained if light had both particle and wave properties. Indeed, particles such as electrons and x-rays appeared to have both discrete energy states and momentum, properties similar to those of light. None of the classical, or Newtonian, laws could account for such behavior, and such inadequacies led scientists to search for new concepts in the consideration of the nature of reahty. [Pg.161]

It is possible to parametarize the time-dependent Schrddinger equation in such a fashion that the equations of motion for the parameters appear as classical equations of motion, however, with a potential that is in principle more general than that used in ordinary Newtonian mechanics. However, it is important that the method is still exact and general even if the trajectories aie propagated by using the ordinary classical mechanical equations of motion. [Pg.73]

All of eighteenth- and nineteenth-century mathematical physics was based on continua, on the solution of second-order partial differential equations, and on microscopic extensions of macroscopic Newtonian ideas of distance-dependent potentials. Quantum mechanics (in its wave-mechanical formulation), classical mechanics, and electrodynamics all have potential energy functions U(r) which are some function of the interparticle distance r. This works well if the particles are much smaller than the distances that typically separate them, as well as when experiments can test the distance dependence of the potentials directly. [Pg.68]

In molecular dynamics applications there is a growing interest in mixed quantum-classical models various kinds of which have been proposed in the current literature. We will concentrate on two of these models the adiabatic or time-dependent Born-Oppenheimer (BO) model, [8, 13], and the so-called QCMD model. Both models describe most atoms of the molecular system by the means of classical mechanics but an important, small portion of the system by the means of a wavefunction. In the BO model this wavefunction is adiabatically coupled to the classical motion while the QCMD model consists of a singularly perturbed Schrddinger equation nonlinearly coupled to classical Newtonian equations, 2.2. [Pg.380]

The temporal behavior of molecules, which are quantum mechanical entities, is best described by the quantum mechanical equation of motion, i.e., the time-dependent Schrdd-inger equation. However, because this equation is extremely difficult to solve for large systems, a simpler classical mechanical description is often used to approximate the motion executed by the molecule s heavy atoms. Thus, in most computational studies of biomolecules, it is the classical mechanics Newtonian equation of motion that is being solved rather than the quantum mechanical equation. [Pg.42]

Boltzmann s tombstone in Vienna bears the famous formula 5 = k log W (W = Wahrscheinlichkeit—probability) that was a signature of his audacious concepts. The alternative formula (13.69) (which reduces to Boltzmann s in the limit of equal a priori probabilities pa) was ultimately developed by Gibbs, Shannon, and others in a more general and productive way (see Sidebar 13.4), but the key step of employing probability to trump Newtonian determinism was his. Boltzmann was long identified with efforts to establish the //-theorem and Boltzmann equation within the context of classical mechanics, but each such effort to justify the second law (or existence of atoms) in the strict framework of Newtonian dynamics proved futile. Boltzmann s deep intuition to elevate probability to a primary physical principle therefore played a key role in efforts to find improved foundation for atomic and molecular concepts in the pre-quantum era. [Pg.451]

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