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<\/h2>\nNEWTON'S FIRST LAW<\/h2>\n
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Newton's first law, also known as Newton's Law of Inertia, tells us that if no external force acts on a body, it will remain at rest or move in rectilinear motion at a constant speed.<\/p>\n
Motion is relative, meaning that it depends on the observer describing the motion. For example, for a passenger on a bus, the passenger sitting next to the bus is moving, while for someone looking at the bus from the outside, the passenger is moving at the speed of the bus. You need a reference system to refer to the motion.<\/p>\n
Newton's first law is used to define the reference systems known as\u00a0Inertial reference systems<\/b>. Reference systems are those systems from which a body on which no net force acts is observed to move with constant velocity.<\/p>\n
In the study of mechanics on Earth, assuming a fixed observer on Earth is a good approximation of an inertial system.<\/p>\n<\/div>\n
NEWTON'S SECOND LAW<\/h2>\n
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In the Newton's first law<\/a> We have seen that it takes a force for a body to change its state of either rest or rectilinear motion. Forces are the result of the action of one body on another.<\/p>\n The Second Law of Motion relates the motions of bodies to forces. The statement of Newton's Second Law tells us that the force applied to a body is proportional to the acceleration of the body and its mass. The formula with which to express this second law is:<\/p>\n F = m a<\/i><\/p>\n Both force and acceleration are vector quantities, i.e. they have, in addition to a value, a direction and a sense. Newton's second law must therefore be expressed as:<\/p>\n F<\/b>\u00a0= m\u00a0a<\/b><\/p>\n The unity of force in the\u00a0International System<\/i>\u00a0is the\u00a0Newton<\/i><\/b>\u00a0and is represented by\u00a0N<\/b>. A\u00a0Newton<\/i>\u00a0is the force to be exerted on a body of\u00a0one kilogram of dough<\/b><\/i>\u00a0to acquire an acceleration of\u00a01 m\/s2<\/sup><\/i><\/b>that is,<\/p>\n 1 N = 1 Kg - 1 m\/s2<\/sup><\/b><\/p>\n Newton's second law formula can be applied as long as the mass is constant. Sometimes the mass is not constant, for example in the case of a rocket burning fuel. A generalisation of Newton's second law is to define the magnitude of the quantity of motion.<\/p>\n The\u00a0amount of movement<\/b>\u00a0which is represented by the letter\u00a0p<\/b>\u00a0and is the product of the\u00a0mass of a body times its velocity<\/i>i.e:<\/p>\n p<\/b>\u00a0= m -\u00a0v<\/b><\/p>\n The quantity of motion is also known as linear momentum. It is a vector quantity and is measured in\u00a0Kg-m\/s\u00a0<\/b>. In terms of quantity of motion, Newton's second law is expressed as follows:<\/p>\n F<\/b>\u00a0= dp<\/b>\/dt<\/p>\n The Force acting on a body is equal to the time variation of the quantity of motion or linear momentum: From this expression of Newton's second law we can derive the\u00a0Principle of conservation of the quantity of motion. <\/b>If the acting forces are zero, i.e. we have this equation:<\/p>\n F=0\u21d2dp\/dt=0\u21d2p=cte Conservation of the quantity of motion can also be generalised to a\u00a0particle system<\/strong>. A particle system is a set of bodies or particles whose motion we want to study.<\/p>\n p=p1+p2+p3+...+p<\/p>\n Although the quantity of motion of the system remains constant, the quantity of motion of each particle can vary. The principle of conservation of the quantity of motion is a fundamental principle that holds without exception and has been confirmed experimentally. The variation of the quantity of motion is known as the impulse<\/a>.<\/p>\n<\/div>\n <\/p>\n As discussed in the\u00a0Newton's Second Law<\/a>\u00a0forces are the result of the action of one body on another.<\/p>\n Newton's third law is known as\u00a0Principle of action and reaction. <\/b>This law states that\u00a0if a body A exerts an action on another body B, the latter exerts on A another action of equal and opposite direction<\/i>.<\/p>\n This is something that we can see on a daily basis on numerous occasions. For example, we can find it in these cases:<\/p>\n Even if the action and reaction pairs have the same value and opposite directions,\u00a0are not cancelled<\/b>\u00a0each other, since\u00a0act on different bodies<\/b>.<\/p>\n<\/div>\n <\/p>\n <\/p>\n If there are any important laws in physics, particularly in mechanics, they are the Newton's Laws<\/strong>. Isaac Newton enunciated the 3 laws of motion of bodies. With these 3 laws, the motion of any body can be practically defined, based on the forces acting on it. All aspects of mechanics, on a terrestrial scale, are covered by Newton's Laws. Later, with relativity and other theories, it was realised that at near-light speeds and with all the singularities that appear in space, Newton's laws were not applicable. However, on Earth, these 3 laws are perfectly valid to define the forces and motions of objects.<\/p>\n ENUNCIATION OF NEWTON'S 3 LAWS Newton's First Law or Law of Inertia Every body remains in its state of rest or uniform rectilinear motion if there is no force to pull it out of it. Second law or fundamental principle of dynamics The acceleration of an object is directly proportional to its [...]<\/p>","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"_acf_changed":false,"footnotes":""},"acf":[],"yoast_head":"\n
\nm=cte\u21d2v=cte<\/p>\n<\/div>\nNEWTON'S THIRD LAW<\/h2>\n
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ABOUT NEWTON'S LAWS<\/h2>\n
EXPERIMENTS WHERE NEWTON'S LAWS ARE APPLIED<\/h2>\n
Pulley Experiment<\/a><\/h3><\/div>\n\n<\/strong> In this experiment, with a set of pulleys, we can learn about force distributions and Newton's laws, applying them to how pulleys work and how they work correctly to reduce weight. <\/div>\n\n<\/div>\n
Chemical Rocket Experiment<\/a><\/h3><\/div>\n\n<\/strong> In this simple but fun experiment we are going to make a homemade rocket. The rocket will be propelled with citric acid and bicarbonate, and when it comes into contact with water, it will shoot up.<\/div>\n\n<\/div>\n
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MORE CLASSICAL PHYSICS TOPICS<\/h2>\n
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