NEWTON’S LAWS OF MOTION

Each of Newton’s laws of motion has mathematical and physical meanings that are necessary to comprehend motion in our universe. These equations of motion have an almost infinite number of applications.

Newton’s laws essentially outline the mechanisms by which motion changes, specifically how such changes are related to force and mass.

In his book “Philosophiae Naturalis Principia Mathematica” (Mathematical Principles of Natural Philosophy), which is commonly referred to as the “Principia,” Newton presented the three laws in 1687. He also introduced his theory of universal gravitation at this time, creating the foundations of classical mechanics in a single volume.

Newton’s 3 laws of motion

The cornerstone of classical mechanics is Newton’s laws of motion, which are three claims that describe the relationships between the forces acting on a body and its motion. Isaac Newton, an English physicist and mathematician, was the first to state them.

Newton’s First Law of Motion

“Unless it is compelled to change its state by forces applied to it, everybody remains at rest or in uniform motion along a straight line.”

The Law of Inertia, or just inertia, is a term used to describe this phenomenon. It basically says two things:

• A motionless thing will remain motionless until a force acts on it.
• Until a force acts on an item in motion, it will not alter velocity (or stop).

For most people, the first point is self-evident, but the second may require some consideration. Things don’t move indefinitely, as everyone knows.

The directions are critical in this process since both velocity and force are vector values. If a downward force (such as gravity) operates on an item with no upward force, the object will accelerate downhill vertically. However, there will be no change in the horizontal velocity.

Even if gravity imposed a force (and thus acceleration) in the vertical direction, if I throw a ball off my balcony at 3 metres per second horizontally, it will strike the ground at 3 metres per second horizontally (ignoring the force of air resistance). The ball would have continued in a straight route had it not been for gravity.

Newton’s Second law of Motion

“The acceleration produced by a specific force applied on a body is proportional to the force’s magnitude and inversely proportional to the body’s mass.”

∑​ F = ma

The second law’s mathematical expression is presented here, with F denoting force, m denoting mass, and a denoting acceleration.

This formula is very useful in classical mechanics since it allows you to immediately translate the acceleration and force acting on a given mass. A lot of classical mechanics boils down to implementing this formula in diverse situations.

The net force, or the sum of all the forces, is indicated by the sigma symbol to the left of the force. The net force and acceleration are both vector values, thus their direction will be the same.

When all of an object’s net forces add up to zero, the state indicated by Newton’s First Law is reached: the net acceleration must be zero. Because all objects have mass, we know this (in classical mechanics, at least). If the object is already travelling, it will continue to do so at a constant velocity until a net force is applied. Without a net force, an object at rest will not move at all.

Newton’s Third law of Motion

“Every action is always counterbalanced by an equal response; or, the mutual activities of two bodies on each other are always equal and directed to opposing parts.”

The Third Law can be illustrated by two interacting bodies, A and B. FA is defined as the force exerted on body A by body B, while FA is defined as the force exerted on body B by body A. The magnitude of these forces will be equal, and their directions will be opposing. In terms of maths,

FB = – FA

or

FA + FB = 0

However, this is not the same as having no net force. When you apply a force on an empty shoebox on a table, the shoebox returns the same force to you. This doesn’t seem right at first – you’re clearly pushing on the box, but it’s not pushing back. Remember that while force and acceleration are related by the Second Law, they are not identical!

The force you exert causes the shoebox to accelerate away from you because your mass is significantly more than its mass. The force it exerts on you isn’t strong enough to create significant acceleration. Not only that, but as it pushes on the tip of your finger, your finger pushes back into your body, and the rest of your body pushes against the finger, and your body pushes on the chair or the floor (or both), all of which keeps your body from moving and allows you to keep your finger moving to continue the force. Nothing is pushing against the shoebox to keep it from moving. If, on the other hand, the shoebox is adjacent to a wall and you push it toward it, the shoebox will push against the wall, which will push back. At this moment, the shoebox will come to a halt. You can try to shove it through the wall, but the box will break because it isn’t robust enough to withstand that much effort.

CONCLUSION

Sir Isaac Newton (1642-1727) was a British scientist who is regarded as the best physicist of all time in many ways. Though there were notable forerunners such as Archimedes, Copernicus, and Galileo, it was Newton who fully defined the technique of scientific investigation that would be followed throughout history.

Aristotle’s account of the physical universe has been insufficient for nearly a century to understand the nature of movement (or the movement of nature, if you will). Newton tackled the challenge and came up with “Newton’s three laws of motion,” which are three broad rules governing how objects move.

At some point in their lives, almost everyone has played tug of war. A person or group of people grabs the ends of a rope and tries to pull against the person or group on the other end, usually past a marker (or, in more entertaining versions, into a mud pit), demonstrating that one group is stronger than the other. In a tug of battle, Newton’s three laws are visible.