## 03 Jul Vivid Vision of Newton’s Laws and Their Applications

17^{th} century British physicist and mathematician Sir Isaac Newton was a maverick figure from the scientific revolution. Today, more than 300 years since his time, much of our fundamental understanding of modern physics and mathematics still depends on his works.

Among the countless branches in academics where Newton left his everlasting mark, he is most remembered for his contributions to the development of the Calculus in mathematics, and his imperative laws of motion and universal gravitation, which he published in his monumental scholarly work, Philosophiæ Naturalis Principia Mathematica*. *

These two laws govern a fundamental and foundational structure to the modern study in motion and gravity. The applications for Newton’s laws in everyday life are endless and diverse in their relevance to almost every aspect in life. Staying true to the goal for a concise theoretical understanding of these laws, we shall explore their applications in everyday life.

**Newtonian laws of Motion: Overview**

Isaac Newton’s 3 laws of motions gave us the foundation to classical mechanics. These three laws explore the physical relationship between a body and external forces acting upon it, and the body’s motion in response to these forces. The three fundamental laws of motion according to Newton are:

**First law of motion**

Newton’s first law, also referred to as law of inertia, states that the net force, or sum of all forces acting on the object is zero, then that object’s velocity will stay constant. This implies that an object at rest or in motion will remain at rest or maintain its velocity respectively, unless any external force acts upon the body, which is the principle of uniform motion.

**Second law of motion**

The second law states that the net force acting on an object will be equal to the rate of change of the body’s linear momentum.

**Third law of motion**

Newton’s third law of motion state that all forces acting between two independent objects exist in equal magnitude and opposite direction.

**Applications for Newton’s laws of motions: A world of unified quantification in Physics**

Newton’s laws are applicable to bodies with single-point mass. So when applied to solve equations regarding motion, the size and shape of the body are unaccounted for, to give focus to its motion. So we can study the orbital motion of a planet around its parent star, since the size of a planet is minute compared to its orbital plane or distance covered. Read here how to **make the maximum use of technology in classroom**.

Newton himself applied his laws of motion in his book, combining them to his laws on universal gravitation to explain the Keller model of planetary motion. Newtonian laws of motion can be applied to explain or quantify the following phenomena:

- Normal forces.
- Static frictional forces.
- Kinetic frictional forces.
- Tension forces.
- Planetary forces of gravitation and planetary motion.
- Explaining gravitational fields, and force in classical dynamics or Newtonian dynamics.
- One-dimensional motion.
- Free-fall or constant acceleration.
- Motion in a viscous fluid.

**Restrictions in applications for Newton’s laws in modern physics**

While so much of our everyday applications in motion, dynamics and gravitational quantification are satisfied by Newtonian laws on forces and universal gravitation, it can only account for calculations where velocities in study are much less than the speed of light.

Ever since the advent of special relativity, our understanding about motion at the speed of light and forces in the subatomic level has changed and cannot be explained by classical mechanics.