It is assumed that internal interaction forces obey Newton's third law of motion in its strong form, that is, that the forces between particles are equal and opposite and act along the line between the particles.

Understandably, recoil of a gun firing a projectile at 17 MJ or more will increase directly with the increase in muzzle energy in accordance to Newton's third law of motion and successful implementation of recoil reduction mechanisms will be vital to the installation of an ETC powered gun in an existing vehicle design.

This explanation relies on the second and third of Newton's laws of motion: The net force on an object is equal to its rate of momentum change, and: To every action there is an equal and opposite reaction.

In conjunction with this force by the air on the airfoil, the airfoil imparts an equal-and-opposite force on the surrounding air that creates the downwash, in accordance with Newton's third law.

Although originally expressed in Newton's third law, the conservation of linear momentum also holds in special relativity ( with a modified formula ) and, with appropriate definitions, a ( generalized ) linear momentum conservation law holds in electrodynamics, quantum mechanics, quantum field theory, and general relativity.

Propeller dynamics can be modelled by both Bernoulli's principle and Newton's third law.

Newton's third law describes the transfer of energy for reaction turbines.

* Newton's third law of motion

Newton's third law describes the transfer of energy for reaction turbines.

Thrust is a reaction force described quantitatively by Newton's second and third laws.

In doing so, the ski pushes snow forward and to the side, and thus by Newton's third law, the snow pushes the skier back and to the opposite side.

Newton's third law of motion is widely used in the study of animal locomotion: if at rest, to move forwards an animal must push something backwards.

There is no analogue of Newton's third law in this theory.

On most propeller powered aircraft, the rotation of the propeller ( s ) induces a counteracting roll movement due to Newton's third law of motion, in that every action has an equal and opposite reaction.

According to Newton's third law, the force that body 2 exerts on body 1 is equal and opposite to the force that body 1 exerts on body 2:

The concept applies Newton's third law: the exhaust directed upward causes a reciprocal force downward.

Isaac Newton was the first to enunciate the conservation of momentum in its modern form, and showed that it was a consequence of Newton's third law.

This requirement has been very influential in the past, in the first place as a result of direct observation of causal processes ( like pushing a cart ), in the second place as a problematic aspect of Newton's theory of gravitation ( attraction of the earth by the sun by means of action at a distance ) replacing mechanistic proposals like Descartes ' vortex theory ; in the third place as an incentive to develop dynamic field theories ( e. g., Maxwell's electrodynamics and Einstein's general theory of relativity ) restoring contiguity in the transmission of influences in a more successful way than did Descartes ' theory.

In all cases, aerodynamic lift is associated with pressures on the wing that sum over the area of the flight surfaces to create the lift force, and there is a net movement of air in the opposite direction from the force which is indirectly created by these pressures, in accordance with Newton's third law of motion.

* Reaction ( physics ), as defined by Newton's third law

Both methods yield thrust due to Newton's third law — every action has an equal and opposite reaction.

Lenz's law is a common way of understanding how electromagnetic circuits obey Newton's third law and the conservation of energy.

In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses ( ejecta ), according to Newton's third law.

Since, by Newton's third law,, it follows that the ratios of the energies is given by:

Instead Neptune was predicted using Newton's law of universal gravitation.

* Conservation of Momentum: This equation applies Newton's second law of motion to a continuum, whereby force is equal to the time derivative of momentum.

This can be equated with the mass of the ion, m, via Newton's law ( F = ma ):

These arguments, and a discussion of the distinctions between absolute and relative time, space, place and motion, appear in a Scholium at the very beginning of Newton's work, The Mathematical Principles of Natural Philosophy ( 1687 ), which established the foundations of classical mechanics and introduced his law of universal gravitation, which yielded the first quantitatively adequate dynamical explanation of planetary motion.

When a body is acted upon by external contact forces, internal contact forces are then transmitted from point to point inside the body to balance their action, according to Newton's second law of motion of conservation of linear momentum and angular momentum ( for continuous bodies these laws are called the Euler's equations of motion ).

: ( Newton's second law of motion )

Newton's law of motion for a particle of mass m written in vector form is:

The dynamics of a mass, m, expressed using Newton's second law of motion ( F = ma ), becomes in polar coordinates:

Now, using Newton's second law we can write ( using convenient units ):

General relativity generalises special relativity and Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime.

The first step is the realization that classical mechanics and Newton's law of gravity admit of a geometric description.

Such deviations are caused by external forces acting on a body in accordance with Newton's second law of motion, which states that the net force acting on a body is equal to that body's ( inertial ) mass multiplied by its acceleration.

According to Newton's law of gravity, and independently verified by experiments such as that of Eötvös and its successors ( see Eötvös experiment ), there is a universality of free fall ( also known as the weak equivalence principle, or the universal equality of inertial and passive-gravitational mass ): the trajectory of a test body in free fall depends only on its position and initial speed, but not on any of its material properties.

For weak gravitational fields and slow speed relative to the speed of light, the theory's predictions converge on those of Newton's law of universal gravitation.

In the classical limit, the theory would reduce to general relativity and conform to Newton's law of gravitation in the weak-field limit.

It consists of a mass m, which experiences a single force, F, which pulls the mass in the direction of the point x = 0 and depends only on the mass's position x and a constant k. Newton's second law for the system is

Newton's second law for damped harmonic oscillators is then

In an inertial frame, Newton's first law ( the law of inertia ) is satisfied: Any free motion has a constant magnitude and direction.

Newton's second law for a particle takes the form:

In contrast, Newton's second law in a rotating frame of reference, rotating at angular rate Ω about an axis, takes the form:

In both cases, application of Newton's second law would not work for the rotating observer without invoking centrifugal and Coriolis forces to account for their observations ( tension in the case of the spheres ; parabolic water surface in the case of the rotating bucket ).

Within the realm of Newtonian mechanics, an inertial frame of reference, or inertial reference frame, is one in which Newton's first law of motion is valid.