**Herong's Notes on Physics** - Version 3.21, by Dr. Herong Yang

Who Is Newton?

This section provides a quick introduction of Issac Newton and his main contribution to physics, Newton's Laws of Motion.

**Who Is Newton?**
Newton, full name Isaac Newton, was an English physicist and mathematician.
He was born on December 25, 1642, at Woolsthorpe, England, and die on March 31, 1727 at London, England.

Newton's main contribution in physics is the discovering of 3 principals on motion called Newton's Laws of Motion, published in a series of 3 books called "Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy)" in 1687:

- Newton's First Law of Motion - If the net force acting on an object is zero, then the velocity of the object is constant.
- Newton's Second Law of Motion - The acceleration of an object is directly proportional to the net force acting on the object, and inversely proportional to the mass of the object.
- Newton's Third Law of Motion - If a force is exerted by one object to another object, another force is simultaneously exerted by the second object to the first object with equal strength and opposite direction.

*Last update: 2014.*

Table of Contents

Introducion of Frame of Reference

Falling Ball in Earth Frame of Reference

Falling Ball in Elevator Frame of Reference

Introduction of Special Relativity

Time Dilation in Special Relativity

Length Contraction in Special Relativity

The Relativity of Simultaneity