Isaac Newton’s story of how an apple falling from a tree that hit his head inspired him to formulate a theory of gravitation is one that all school children grow up hearing about. Newton is arguably one of the most influential scientific minds having ever lived. He has published books such as Arithmetica Universalis, The Chronology of Ancient Kingdoms, Methods of Fluxions, Opticks, the Queries, and most famously, Philosophiæ Naturalis Principia Mathematica. He formulated the three laws of gravitation, discovered the generalized binomial theorem, developed infinitesimal calculus (sharing credit with Gottfried Wilhelm Von Leibniz, who developed the theory independently) and worked extensively on optics and refraction of light. Newton changed the way that people looked at the world they live in and how the universe works.
Newton was educated in the King’s School, Grantham from the age of twelve to seventeen where he learned only Latin and no mathematics. His mother removed him from school in the hopes of getting him to join the family profession of farming, but he hated it and failed at it. He was later re-enrolled in the school after a master at the King’s School persuaded his mother to do so. In 1661, Newton was admitted into Trinity College, Cambridge at a time when the college’s courses were mostly based on Aristotle’s teachings. Newton supplemented this with then modern philosophers such as Descartes, astronomers such as Galileo Galilee and Thomas Street, and Johannes Kepler.
Newton had a dispute with Leibniz when both of them independently developed the infinitesimal calculus at around the 1660s. In 1699, members of the Royal Society accused Leibniz of plagiarism. This accusation was proven false on 1711 when it was later found that Newton had concluded his study with remarks on Leibniz. The dispute marred the lives of both Isaac Newton and Gottfried Wilhelm Von Leibniz until the death of the later at 1716.
Even though huge group of people of the world believe that the story of an apple that Newton experienced is a myth. But his consociates named as William Stukeley gives a confirming remark about it which is later followed by many peoples. They confirmed that the apple story was real, and it happened. But they deny the fact that apple hit Newton’s head. Stukeley in his book Memoirs of Sir Isaac Newton’s life has mentioned as well as recorded about the conversation that he made with Newton on 15th April 1726,
According to Stukeley, one both of them were moving in the garden where they drank a cup of tea. While they were having a cup of tea, they were sitting under an apple tree. In the meantime, Newton spoke about the fact that his mind was pre-occupied with the concept of gravitation and the situation under the tree is same as when his mind conceived the idea of gravitation. Newton asked the question regarding the falling of an apple perpendicularly to the ground when they noticed an apple falling from the tree. His mood completely changed and was dipped in a complete, thoughtful situation. One prominent question he thought was the falling of an apple towards the center of the earth rather than falling sideways or going up. This question came out with an answer, and the answer was that the earth’s gravity pulls any objects towards its center. So, Newton concluded that every matter has a power to attract another matter towards itself and the concentrated mass of the earth at its center makes any object fall towards the center rather than in any other sides. He also concluded that the attracting power of any object is proportional to its mass. So, not only an apple falls towards the center of the earth because the earth attracts it, but even an apple attracts the earth towards itself.
Isaac Newton was knighted by Queen Anne on April, 1705 during her visit to Trinity College. It is said, however, that the knighthood was motivated by political considerations rather than by his scientific achievements. Newton was the second scientist to be knighted after Sir Francis Bacon.
Few people know that Isaac Newton spent half of his life in fruitless pursuit of the philosopher’s stone. This resulted in mercury poisoning that many speculate contributed to his eccentricity in his later life. Newton left this world on his sleep on March 20, 1727 in London. Westminster Abbey is the place where he was buried later.
The Three laws of Gravitation
Newton’s most famous contribution to science is the postulation of the three laws of gravitation, which he wrote about in his book Philosophiæ Naturalis Principia Mathematica.
The First Law:
Newton’s first law of motion (also known and defined as the inertia law) states that, “An object at rest tends to stay at rest and that an object in uniform motion tends to stay in uniform motion unless acted upon by a net external force.” This first law of Newton also describes the force of inertia and this is the force that keeps the body in the state of rest or motion until and unless there is an external force applied to it.
The following image, taken from the NASA educational website explains how Newton’s first law works when flying a kite. The forces acting on the kite are its weight (mass multiplied by acceleration due to gravity), the aerodynamic lift and drag, and the tension in the control line. When all these forces are balanced, the kite holds a fixed attitude. If any of this alters because of say, an increase in wind speed, the forces become unbalanced, and the kite’s position is changed until a new equilibrium is obtained. Other examples include how our body moves forward after a car we are in sudden stops, and how a basketball rolling on the floor of the court will eventually stop because of the force of friction acting on it.
The Second Law:
According to the second law of motion explained by Newton, “An applied force (F) of an object equals the rate of change in momentum (P) with time. This law can be expressed mathematically as,
F=dpdt=d(mv)dt
This law can only be applied to objects of constant mass (m) so m can be brought out of the derivative operator. Acceleration is rate of change in velocity, so the equation can then be written in the form that is most widely recognized:
F=ma
Force is a vector quantity, so the resultant forces at the y and x axes must be considered separately. In case of an inclined plane, the force of gravity is also at play and must be considered.
In the above diagram (a), a basketball player throws the basketball using some amount of force F that results into some amount of acceleration, a1 (ignoring the effect of gravity). When he uses the same amount of force to move the car, he produces much less acceleration because the mass of the car is greater. Other examples include swinging people of different mass, which require different force for the same acceleration and why objects in free fall have the same acceleration even when they have different masses.
The first and the second law broke away from Aristotle’s explanation of motion, because Aristotle believed that the force was only required to change an object’s state of motion.
The Third Law:
Newton’s third law of motion states that, “Every action has an equal but opposite reaction.”
In the above image, the gun recoils when the bullet leaves the gun because of Newton’s third law of motion. Other examples include the launch of a rocket, and a car crashes (for example, the force of the car produced from its mass and acceleration as it hits a tree will result to equal force acting on the car).
For the purpose of concentrating the attention on the motion of the body, the Newton's laws is applied to objects that have the single point mass. In such case, the size and shape of the body under consideration is ignored or neglected. With the distance between the objects larger than the size of the object or a situation in which we do not care about the rotation or deformation of the body, this analysis can be done in better way. This consideration gives every individual to consider the earth as a particle to do the analysis based on its orbital motion around a star.
Here mass, acceleration, momentum, and force are the quantities that are defined externally i.e. they are the externally defined quantities. It is also equally true that Newton’s laws of motion do not suffice to characterize the motion of deformable and rigid bodies. After the generalization of the laws of motion propounded by Newton in 1950 by Leonhard Euler, the laws were equally accepted for rigid bodies, and this was later called as Euler's laws of motion. This theory was later applied in the deformable bodies, and the laws were equally true in that condition, as well. Even though this law is outmoded by laws of relativity, but this law is equally applicable in the situation where the speed of objects are less than the speed with which light travels.
Works Cited
"2012 BMW 1-Series CRASH TEST." YouTube. N.p., n.d. Web. 15 Apr. 2014.
"The Application of Newton’s Third Law of Motionin a car crash? – Follow Up." Shiv's World of Physics. N.p., n.d. Web. 15 Apr. 2014.
"Isaac Newton Biography - Newton's Life, Career, Work - Dr Robert A. Hatch." College of Liberal Arts and Sciences | The University of Florida. N.p., n.d. Web. 15 Apr. 2014.
"Isaac Newton." Wikipedia, the free encyclopedia. Wikimedia Foundation, Inc, n.d. Web. 15 Apr. 2014.
"Newton's 3 (three) Laws of Motion." YouTube. N.p., n.d. Web. 15 Apr. 2014.
"Newton's First Law Applied to a Kite." NASA - Title N.p., n.d. Web. 15 Apr. 2014.
"Newton's Second Law of Motion (Definition and Examples)." YouTube. N.p., n.d. Web. 15 Apr. 2014.
"Newton's Three Laws of Motion." N.p., Web. 15 Apr. 2014.
"Newton’s Second Law of Motion: Concept of a System." OpenStax_CNX. N.p., n.d. Web. 15 Apr. 2014.
"TheScienceClassroom Newton's Second Law of Motion." N.p., Web. 15 Apr. 2014.
Siyavula. "Newton's Laws." Everything Science. N.p., n.d. Web. 15 Apr. 2014.
"Use Newton's first law of motion to explain why a basketball rolls across the court? - Homework Help .com." eNotes. N.p., n.d. Web. 15 Apr. 2014.
