Mechanics

The field of physics that mainly focuses on the study of motion and the forces and displacement associated with it along with the effects of these bodies on their environment is called mechanics.  

The major branches of mechanics are mainly two in number - classical mechanics and quantum mechanics. Therefore, read this article to know some basic information about mechanics and the difference between classical mechanics and quantum mechanics.

Classical Mechanics

When an object moves it gets exposed to various forces. Classical mechanics is concerned with the understanding of this process. It also deals with stationary objects and the forces that are acting on them at any point in time.

This is the answer to ‘what is classical mechanics?’

From the name classical mechanics, it is hinted that situations, where an object travels with velocity, don't fall under this field. This velocity can be associated with an atomic scale phenomenon or a sizable fraction of the speed of light.

In such cases, this velocity is not a matter of concern for classical mechanics since the atomic phenomenon falls under quantum mechanics and Einstein's theory of relativity. Moreover, classical mechanics is older than quantum mechanics.

The classical mechanic's laws were theorized by Sir Isaac Newton in 1687 whereas Quantum mechanics and the theory of relativity both were stated in the 20th century. 

Classical mechanics and its laws are used in various aspects of the modern world. These laws play a very significant role in calculating the trajectories of planets, balls, bullets, and even spacecraft.

The classical laws of mechanics can effectively be used for predicting the position-time relation of a rolling cylinder that's going down or a pendulum that is oscillating.

They can also be used to calculate the tension in a string which is enabling a picture to hang from a wall.

Therefore classical mechanics and its practical importance play a huge role in the modern world that is filled with buildings, cars, planes, missiles, etc. Hence, a compelling intellectual reason also exists besides professional needs for knowing this field.

The main importance lies in the capability of classical mechanics to explain a wide range of phenomena through simple and minimal principles.

Quantum Mechanics

The other important field of mechanics is quantum mechanics.

It mainly concerns phenomena and the logic behind the mechanics of particles on very minute scales. However, there are also some macroscopic systems dealing with quantum mechanics. 

The term Quantum can be used in contrast to classical mechanics since some quantities only take discrete values. In quantum mechanics, every particle has a distinct wave equation and features wavelike properties.

The behaviors of these waves are maintained by the Schrodinger equation and this equation is unique in certain ways from the other available wave equations.

This field of mechanics can be seen as a system that is directed by a wave equation.

However, although actual waves can be dealt with easily, quantum mechanics constitutes some unique combination of perplexing, weird, and subtle things. Some of these are wave-particle duality and Bell's theorem's hidden variables and measurement issues.

The quantum mechanics meaning is often very hard to grasp, but the application of this field of mechanics to any physical system and finding out its behavior is very easy.

Statistical Mechanics

The aspect of statistical mechanics that deals with extending classical thermodynamics and treating it are termed equilibrium statistical mechanics or statistical thermodynamics. It can be used for getting results for real systems. Moreover, it can also be used for solving Schrodinger's equation for 1 quantity.

Statistical mechanics is applied for getting answers in aspects of thermodynamics wanting the entropy to be maximum at equilibrium. 

Whereas thermodynamics mainly focuses on heat and the direction in which heat flows, statistical mechanics mainly provides a microscopic perspective of heat concerning the structure of a matter and finds a process for or evaluation of matter's thermal properties such as heat capacity.

Therefore these are some basic concepts of mechanics and its disciplines.

To get a more detailed insight into this interesting field of physics, you can find it in any good physics mechanics chapter.