We explain who Isaac Newton was and the main events in his life. Furthermore, the characteristics of it and laws of motion of it.
Who was Isaac Newton?
Isaac Newton was an English scientist who devoted himself primarily to physics and mathematicsbut who also dabbled in philosophy, alchemy (a previous form of chemistry) and theology.
Among his contributions to scientific knowledge are:
- The discovery of the color spectrum contained in light.
- The first hypothesis on the existence of particles that make up light.
- The study of temperature transmission through convection.
However, His most important contributions are his three laws of motionwhich are explained below. These laws were able to explain the movement of the stars based on the same physical principles that explain movement on the Earth’s surface.
See also: Newton’s Laws
Biography of Isaac Newton
Isaac Newton was born on January 4, 1643 in the county of Lincolnshirein a village called Woolsthorpe Manor, which is located north of London, England.
His father, Barnabas Smith, was a farmer who had died at the end of 1642, so Newton He was raised by his mother, Hanna Ayscough.until she married another man, at which point she went to live with her grandparents, until her stepfather died.
From a very young age he showed a talent for inventions.For example, he copied a windmill from his village that worked even better than the original. In 1661 he entered Cambridge University and furthered his studies in optics, geometry and mathematics, and developed a model of a telescope.
In 1693 he suffered a mental crisisalong with periods of depression and paranoia. These conditions are believed to have been caused by accidental mercury poisoning during his experiments. He died on March 20, 1727, at the age of 84.
Law of inertia or Newton’s First Law
“Every body perseveres in its state of rest or uniform rectilinear motion unless it is forced to change its state by forces imposed on it.”
What this law indicates that if an object is at rest, it will continue to be at restand if it is in uniform rectilinear motion it will maintain that motion, unless a force is applied to it (which seeks to stop it, accelerate it or move it in another direction).
This law contradicts Aristotle’s law which held that a body could only be kept in motion if a constant force was applied to it.
Practical application of Newton’s First Law
Knowing that an object will continue in motion once a force is applied to it (and as long as no other force acts on it) is of vital importance.
For example, when considering the safety of a means of transportation. A passenger in a car is in uniform rectilinear motion.
If the car is stopped by an external force, the passenger will continue moving.or, that is, it can hit the windshield or even go through it.
That is why there are seat belts that stop the movement of the passenger at the same time as the movement of the car is stopped.
Why do moving objects stop?
If you turn off the engine of a car that is in uniform rectilinear motion, it will continue in motion, according to Newton’s First Law. However, The car will gradually lose speed and finally stop.. This is because frictional forces (for example, the resistance exerted by the air and the road on the car) are acting on the car.
Knowing these forces allows us to design objects that, due to their shape, reduce the various resistances as much as possible. For example, aerodynamic car designs or the sliding surfaces of skis that reduce friction.
Newton’s First Law and Gravity
In outer space there is no friction since there is no air that can stop objects with its resistance. Therefore, when observing the movement of the Moon around the Earth, Newton came to the conclusion that if the Moon did not fly out of its orbit it was because there was a force that kept it attached to the Earth: gravity.
Fundamental law of dynamics or Newton’s second law
“The change in motion is directly proportional to the force impressed and occurs along the straight line along which that force is impressed.”
With his second law, Newton poses force as a quantifiable phenomenon, that is, the change in the motion of an object allows the force applied to that object to be measured and vice versa. Forces applied to moving objects generate acceleration.
Freefall
In the free fall of objects, the application of Newton’s Second Law is observed: the object is attracted by the force of gravity. Therefore, the object undergoes acceleration.
This is why objects that fall from a certain height reach the ground with less speed than those that fall from a greater height: the greater the height from which an object falls, the longer the time during which it accelerates and, Therefore, it reaches the ground with greater speed.
Simple pendulum
In the pendulum, Newton’s Second Law is observed but in the combination of two forces. On the one hand, When you release a pendulum, gravity exerts a downward force. But at the same time, the pendulum thread also exerts a force, called tension. Tension and gravity are not opposing forces, but rather they combine to create a continuous movement.
Newton’s Third Law: Principle of Action and Reaction
“With every action there is always an equal and opposite reaction”. This means that when one body exerts a force on another (action), it applies the same force but in the opposite direction on the first (reaction).
This law was developed by Newton in a completely original way, unlike the two previous ones, which were based on the work of other physicists. Newton’s Third Law allows us to think of forces as a systemin which bodies relate to each other through opposing forces.
Applications of Newton’s Third Law
Although Newton’s Third Law It is used in the study of particles, we can also observe it in everyday life.For example, when using an oar, we apply a force on the water and the water applies the same force on the oar, but in the opposite direction. That is why when we row “backwards” the boat moves forward.
The principle of action and reaction also must be taken into account when using a firearmThe gun pushes the bullet, which is very small, with some force in one direction but, at the same time, the gun is pushed back with the same force.
Since the gun is much larger than the bullet, the acceleration it suffers is less than that of the bullet, so with a firm grip, its movement can be contained.
Continue with: Galileo Galilei