Overview

Mechanics is the oldest branch of Physics as we know it. It was Sir Isaac Newton who developed Physics, to be particular Mechanics out of Natural Philosophy with the help of Mathematics. He took Galileo's experiments, and his own works, and presented them in a formal manner as the subject of Mechanics. At present Mechanics is the science of motion and the causes behind motion. It forms a central part of all physical science and engineering. Beginning with Newton's laws of motion in the 17th century, the theory has since been modified and expanded by the theories of quantum mechanics and relativity. Newton's theory of mechanics, known as classical mechanics, accurately represented the effects of forces under all conditions known in his time. Even today in all but the extreme situations his laws are used with excellent results, even in manned space exploration.


Mechanics is usually divided into two broad parts:

• Kinematics or the study of the description of motion. Kinematics does not try to find the causes of motion - it's only job is to describe motion in terms of certain quantities like displacement, velocity, acceleration, etc.
  
• Dynamics or the cause-effect study of motion.

Simple Harmonic Motion

A particle is said to execute simple harmonic motion (or SHM) when the acceleration of the particle, that is, the force on it, is directly proportional to the distance of the particle from a fixed point on its path, and this acceleration/force is always directed towards that particular point.

Mathematically, the force on the particle is given by F = -kx where F is the force, k is a constant and x is the distance of the particle from the reference point. It is called Simple Harmonic because we come across a "Simple Harmonic" mathematical function in the displacement vs. time relationship of the motion. Example of such a periodic motion is the motion of a simple pendulum.