Newton's laws of motion

Newton's laws of motionNewton's laws of motion are three physical laws that form the basis of classical mechanics. This law describes the relationship between the forces acting on an object and the motion they produce. This law has been written with a different pembahasaan for nearly three centuries, [1] and can be summarized as follows:

    First Law: Every object will have a constant velocity unless a non-zero resultant force acting on the object. [2] [3] [4] This means if the resultant force is zero, then the center of mass of an object remains at rest or moving at a speed constant (not accelerating).
    Second Law: A body of mass M having the resultant force of F will accelerate a direction similar to the direction of the force, and the magnitude is proportional to F and inversely proportional to M. or F = Ma. It could also mean the resultant force acting on an object is equal to the derivative of the linear momentum of the object with respect to time.
    Third Law: action and reaction force of two objects have the same magnitude, the direction reversed, and the line. This means that if an object A, which gives a force of F on object B, then object B will give a force of-F to object A. F and-F have the same magnitude but different direction. This law is also known as the action-reaction law, with F called the action and-F is a reaction.
The three laws of motion was first summarized by Isaac Newton in his Philosophiae Naturalis Principia Mathematica, first published on July 5, 1687. [5] Newton used his work to explain and investigate the motion of a variety of physical objects and systems. [6] For example, the volume three of the text, Newton showed that the laws of motion combines with the general law of gravity, he can explain Kepler's laws of planetary movements belong.Review
Newton's laws applied to objects that are considered as particles, [7] in the evaluation of such movement, long ignored objects, because the object is calculated to be small, relative to the distance traveled. Changes in shape (deformation) and the rotation of an object is also not considered in the analysis. So the planet can be considered as a point or a particle to be analyzed motion orbit around a star.
In its original form, Newton's laws of motion are insufficient to calculate the movement of the objects that can change shape (not solid objects). Leonard Euler in 1750 introduced a generalization of Newton's laws of motion for a solid called Euler's laws of motion, which in its development can also be used for objects not solid. If any body can be represented as a collection of different particles, and each particle follows Newton's laws of motion, then Euler's laws can be derived from Newton's laws. Euler's law can be regarded as an axiom in explaining the movement of the objects that have dimensions. [8]
When a speed approaching the speed of light, the effects of special relativity must be taken into account. [9]Newton's first lawFile: First law.oggWalter Lewin explains Newton's first law. (MIT Course 8:01) [10]

    Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a Viribus impressis cogitur statum Illum Mutare.


    Law I: Every body will maintain a state of rest or moving uniformly straight, unless there is a force acting to change. [11]
This law states that if the resultant force (the vector sum of all forces acting on the body) is zero, then the velocity is constant. Mathematically formulated to be:

    \ Sum \ mathbf {F} = 0 \ Rightarrow \ frac {d \ mathbf {v}} {dt} = 0.
Meaning:

    An object is stationary will remain stationary unless there is a non-zero resultant force acting on it.
    An object is moving, it will not change speed unless there are non-zero resultant force acting on it.
Newton's first law is the law of inertia explanation of the return that has been described by Galileo. In his book, Newton pays tribute to Galileo for this law. Aristotle argued that each object having an origin in the universe: a heavy object such as a stone would be on the ground and light objects like smoke in the sky. The stars will remain in heaven. He thought that an object is at its natural condition if it does not move, and for an object moving in a straight line at constant speed needed something from the outside that kept pushing the object, otherwise the object will stop moving. But Galileo realized that force is needed to change the speed of the object (acceleration), but speed is not necessary to maintain the style. Same with Newton's first law: Without force means no acceleration, then the object is at a constant speed.Newton's second lawThe second law states that the total force on a particle is equal to the number of linear momentum p changes with time:

    \ Mathbf {F} = \ frac {\ mathrm {d} \ mathbf {p}} {\ mathrm {d} t} = \ frac {\ mathrm {d} (m \ mathbf v)} {\ mathrm {d} t},
Because the law only applies to systems with constant mass, [13] [14] [15] variable mass (a constant) can be excluded from the differential operator using the rules of differentiation. Thus,

    \ Mathbf {F} = m \, \ frac {\ mathrm {d} \ mathbf {v}} {\ mathrm {d} t} = m \ mathbf {a},
With F is the total force acting, m is the mass of the object, and a is the acceleration of the object. The total force acting on a body produces a proportional acceleration.
Increases or decreases the mass of the system will result in a change in momentum. Change of momentum is not the result of force. To calculate the mass of the system can change, it takes a different equation.
In accordance with the first law, the time derivative of momentum is not zero when there is a change of direction, although no change of scale. An example is the uniform circular motion. This relationship also implies the conservation of momentum: When the resultant force acting on the object is zero, the momentum of the object is constant. Any change in the style proportional to the change in momentum per unit time.
This second law needs to change if special relativity into account, because the speed is very high yield masses at speeds approaching no real momentum.Impulse
Impulse J occurs when a force F acting on a time interval Δt, and is given by [16] [17]

    \ Mathbf {J} = \ int_ {\ Delta t} \ mathbf F \, \ mathrm {d} t.
Impulse is a concept used to analyze the impact. [18]Systems with changing mass
Systems with changing mass, such as rocket fuel is used and the rest out of gas, not termasduk in a closed system and can not be calculated by simply changing the mass becomes a function of time in the second law. [14] The reason, as it is written in An Introduction to Mechanics Kleppner and Kolenkow works, is that Newton's second law applies to fundamental particles. [15] In classical mechanics, a particle has a constant mass. In the case of particles in a system that clearly defined, Newton's law can be used by adding up all the particles in the system:

    \ Mathbf {F} _ {\ mathrm {total}} = M \ mathbf {a} _ \ mathrm {AM}
with Ftotal is the total force acting on the system, M is the total mass of the system, and apm is the acceleration of the center of mass of the system.
Systems with varying mass like a rocket or a perforated bucket can not usually be counted as the particle system, then Newton's second law can not be used directly. The new equation is used to solve such problems by rearranging the second law and calculate the momentum carried by mass entering or leaving the system: [13]

    \ Mathbf F + \ mathbf {u} \ frac {\ mathrm {d} m} {\ mathrm {d} t} = m {\ mathrm {d} \ mathbf v \ over \ mathrm {d} t}
with u is the velocity of the mass into or out relative to the center of mass of the main object. In some conventions, big (u dm / dt) on the left side of the equation, which is also called a boost, is defined as the force (force issued by an object in accordance with the change in mass, such as rocket boost) and be included in the size of F. So by changing the definition of acceleration, the equation had become

    \ Mathbf F = m \ mathbf a.
History
Newton's second law in its original language (Latin) reads:

    Lex II: Mutationem motus proportionalem esse vi motrici impressae, et Fieri secundum lineam rectam qua vis illa imprimitur.
Diterjmahkan quite rightly by Motte in 1729 to:


    Law II: The alteration of motion is ever proportional to the motive force impress'd; and is made in the direction of the right line in roomates that force is impress'd.
Which in Indonesian means:


    Second Law: The change of motion is always proportional to the force generated / work, and have the same direction with the normal of the point of tangency, and object styles.
Newton's third lawNewton's Third Law. The ice skater exerts a force on each-other with the same magnitude but opposite direction.Explanation of Newton's third law. [19]"Lex III: Actioni contrariam semper et æqualem esse reactionem: corporum sive duorum actiones in se esse æquales mutuo semper et in partes contrarias dirigi. '"The third law: For every action there is always a reaction equal and opposite direction: or the style of the two objects on each other are always equal and opposite directions. '
Any object push or pull other objects having the same pressure or traction of the objects are pressed or pulled. If you press a stone with your finger, your finger is also pressed by the stone. If a horse pulling a rock using a rope, the horse is also "interested" in the direction of the stone: for rope is used, it will also draw the horse in the direction he pulled the stone by stone in the direction of the horse.
The third law explains that all forces are interactions between different bodies, [20] there is no force acting on only one thing. If object A work force on the object B, object B will simultaneously work on the same style with the object A and the second line style. As shown in the diagram, the launcher Ice (Ice skater) gives the forces on each other with the same magnitude, but opposite directions. Although given the same force, the acceleration is happening is not the same. Launchers are a smaller mass will have a greater acceleration due to Newton's second law. The two forces acting on the third law is the same type style. For example, between the wheels with street alike friction.
In simple, the style is always working on a pair of objects, and never only on an object. So for every style always has two ends. Every end of the style is the same but in the opposite direction. Or a tip of the style is a reflection of the other.
Mathematically, this third law in the form of a one-dimensional vector equation, which can be written as follows. Assume object A and object B exerts a force against each other.

    \ Sum \ mathbf {F} _ {a, b} = - \ sum \ mathbf {F} _ {b, a}
With

    Fa, b are the forces acting on A by B, and
    Fb, a is the forces acting on B by A.
Newton used the third law to reduce the law of conservation of momentum, [21] but with a deeper observation, conservation of momentum is the more fundamental idea (derived via Noether's theorem of relativity Galileo compared to the third law, and remain in force in case that makes Newton's third law as -would not apply. example when the magnetic field has momentum, and in quantum mechanics.The importance of Newton's laws and their validity range
Newton's laws are verified by experiment and observation for over 200 years, and these laws are an excellent approach to the calculation of the scale and speed of the human experience everyday. Newton's laws of motion and law of gravitation general and calculus, (for the first time) to facilitate quantitative explanation of the various physical phenomena.
The third law is also a good approximation for macroscopic objects under everyday conditions. But the law newton (coupled with the general laws of gravity and classical electrodynamics) are not appropriate for use in certain conditions, especially in a very small scale, very high speeds (in khususs relativity, Lorentz factor, the rest mass, and speed must be taken into account in the formulation of momentum ) or very strong gravitational fields. So these laws can not be used to explain phenomena such as conduction of electricity in a semiconductor, the optical properties of a material, the error in the GPS system is not corrected relativistic, and superconductivity. Explanation of these phenomena requires a more complex physical theories, including general relativity and quantum field theory.
In quantum mechanics concepts such as force, momentum, and position defined by linear operators that operate in a quantum state, at a much lower speed than the speed of light, Newton's laws as correct by operators working on classical objects . At speeds approaching the speed of light, the second law remains valid as the original form F = DPDT, who explained that the force is the derivative of the momentum of an object over time, but some of the latest versions of the second law does not apply to relativistic speeds.Relations with the law of conservation
In modern physics, the law of conservation of momentum, energy and angular momentum apply more general than Newton's laws, as they apply to the light and matter, and also in classical physics and the non-classical physics.
Simply put, "Moment, energy and angular momentum can not be created or destroyed."
Because the style is a derivative of the moment, the basic theories (such as quantum mechanics, quantum electrodynamics, general relativity, etc..), The concept of style is not important and is under conservation of momentum.
The standard model can explain in detail how the three fundamental forces known as gauge forces, derived from the exchange of virtual particles. Other styles such as gravity and fermionic degeneracy pressure also arise from the conservation of momentum. Immortality of the 4-momentum in inertial motion through space-time terkurva produce what we call gravitational force in general relativity.
Conservation of energy has been discovered after almost two centuries after Newton's life, there was a long pause is caused by the difficulty in understanding the role of microscopic and invisible energy such as heat and infra-red light.