What is Physics?
The word "Physics" comes from the greek word 'Fusis' which means nature.
So from its name we can say that the physics is branch of science which devoted to the study of nature and natural phenomena.
In other word we can say that physics tell us the reason behind the natural activity like :- Day and Night, Wind Flow, Making of Rainbow, energy Coming from Sun and so on the list is endless. Physics Tell us How Thing Happened.
Physics Tell Us all the event in nature take place according to some basic laws. Thus Physics is the most basic of all the sciences.
Physics Divide in to two part:-
Classical Physics:- The Knowledge of Physics which accumulated until about the year 1900. Its Further Divides in to Three subparts.
Mechanics :- Deal with the theory of motion
Thermodynamics :- Deal with the heat, temperature and behaviour of a system of very large number of particle.
Electromagnetics :- Deals with the study of electricity, magnetism and electromagnetic radiation.
Modern Physics :- recent Knowledge of Physics or beyond the year 1900. Its ides in to two subpart.
Relativity:- Deals with the motion of particle moving with speeds of the order of velocity of light.
Quantum:- Deal with the mechanical behaviour of submicroscopic particle.
Forces in Nature ( Physical Forces ).
In Everyday Observation we say many natural phenomenon like every thing falling back to earth ( Gravitational Force), thing became warm while rubbing ( Friction) , Dust Collected on Things ( Electromagnetic Force ) etc, these all things are happened because of some fundamental natural forces.
All these forces that we encounter in macroscopic world are manifestation of two basic type of forces:
1) Gravitation Forces
2) Electromagnetic Forces,
However, in the microscopic world, there are two more type of forces,
1) The Weak ( nuclear ) Forces.
2) the Strong ( nuclear) Forces.
Hence There are four types of basic forces n nature,governing macroscopic as well as microscopic world.
1) Gravitational Force :- All Particle in this universe exert a gravitational force of attraction upon one another. The magnitude of these forces exerted by a particle of mass m1 on another particle of mass m2 at a distance r from it is given by Newton's Law of Gravitation.
where G is Universal gravitational constant and has the value
2) Electromagnetic Forces :- Force exerted by one particle on another particle because of the electric forces. these forces can calle Electromagnetic Forces. These Forces can either be attractive or repulsive. When two particle carry unlike charges, electromagnetic force is attractive, and when they carry like charges the electromagnetic force is repulsive.
3) Weak Forces :- These Forces were discovered during the study of the phenomenon of β decay , in radioactivity, In β -decay, electrons are emitted from radioactive nucleus. It was believed that β decay occurs when a neutron in the nucleus is convert into a proton and an electron . According theoretical consideration, all β -particle from radioactive nucleus should possess the same energy and hence same velocity.
It was conclude that an electron and an antineutrino interact with each other through weak forces. Thus the weak forces are the forces of interaction between elementary particle of short life times.
The weak forces are 10^25 times stronger than the Gravitational forces.
The weak forces exit between Leptons ( Leptons & Mesons are kind of Elementary Particle ) and Leptons, mesons and Leptons.
4) Nuclear Forces :- The Force that bind the neutrons and protons together in an nucleus is called the strong nuclear forces. It act between two proton and two neutron or proton and neutron, but only if the particle are very close together ( with in 1 fermi 10^-15 m).
We can discuss briefly about each of these force later in individual articles.
Enough of now Thanks for Reading.