Newton’s three laws of motion 

   Isaac Newton is named the father of science and is the first of all modern scientists. One of his famous discoveries is the three laws of motion. It serves as an example to any answer regarding the question – Can the laws of physics be applied everywhere, from the movement of an ant to the momentum that holds all the planets in their place.

   The first law of motion is that a substance or material tends to keep still unless a force is applied that can cause movement. And a  material moving will keep on moving unless a force acts upon it , basically resistive forces. Moving things will move at the same direction and with the same speed or velocity. Motion ( mechanics) or lack of motion cannot change without an unbalanced force .

    The second law of motion

    F=MA

    Newton said that the acceleration of an object is related to the size or magnitude of the force , as it is a vector quantity, also the direction and is inversely related to the mass = 1/m ( this mathematical expression is given to help you understand what is the meaning of inverse relation).

    A=v2-v1/t => Acceleration = velocity 2 - velocity 1 divided by time . 

    By this equation you can surely understand the relation between acceleration and velocity. For example if you give a force of 10 newtons to a glass full of water , there will be more effect  and more acceleration , but if you give the same force to a truck , there will be less effect , simply because the mass of a truck is greater that the mass of a glass full of water. (Acceleration means the rate at which the speed of an object changes) .

    The third law

    Newton stated that if a force is exerted on anything then another force is going to work back upon . The force that is given back is equal. For example, when a ship gets heavy and exerts a force downward towards the water, the water , not becoming deformed, gives an upward force which is equal , thus becoming balanced. This causes the ship to float. But there are some exceptions .When a canon is pushed forward in the air , the reader after reading this law , will expect it to come back and if not, the law will be violet. But - No law is violet!! The cannon ball will not be much effected simply because it has a large mass.

Top 10 physicists of the world :

1.       Isaac Newton :

Notable contribution - laws in optics  

                                         Laws of gravity

                                         Theory of gravity

                                         Calculus

                                         Binomial series
                                         Newton's method

                                        

2.       Albert Einstein :

Notable contribution – general theory of relativity

                                          Special theory of relativity

                                          Photoelectric effect

                                                      Einstein field equations

                                                                Bose–Einstein statistics

·                                                                                 Unified Field Theory

3.       Max Planck :

Notable contribution – quantum theories

                                          Planck’s constant

                                          Blackbody theory

4.       John Scott Russell ( although he is an engineer )

Notable contribution -  Soliton

5.       Stephen Hawkings

Notable contributions – Black hole theory

                                            Baby universes

                                            Big bang theory

6.       Nicola Tesla

        Notable contributions - Alternating current
                                                          Bifilar coil
                                                          Death ray
                                                          Electrogravitics
                                                          Induction motor
                                                          Particle beam weapon
                                                          Rotating magnetic field
                                                          Teleforce
                                                          Telegeodynamics
                                                          Terrestrial stationary waves
                                                          Wireless technology

        6.    Galileo Galiley –

Notable contribution -  Astronomical observations with magnificent results like discovery of

                                          Jupiter

                                          Invented the first telescope

         7. Nicola Tesla

    Notable contributions-Alternating current
                                                  Bifilar coil
                                                  Death ray
                                                  Electrogravitics
                                                  Induction motor
                                                  Particle beam weapon
                                                  Rotating magnetic field
                                                  Teleforce
                                                  Telegeodynamics
                                                  Terrestrial stationary waves
                                                  Wireless technology

         8.  George Ohm

            Notable contributions - Ohm's law
                                                  Ohm's phase law
                                                  Ohm's acoustic law

     9.  Niels Henrik David Bohr

            Notable contributions-Copenhagen interpretation
                                                                  Complementarity
                                                                 Bohr model
                                                                 Sommerfeld–Bohr theory
                                                                 BKS theory
                                                                 Bohr magneton

   10 .  Shottendranath Bosu :

           Notable contributions – Discovery of Boson 

                              Manhattan project                                 

What can ever be more dangerous, disastrous and catastrophic to our World then a nuclear bomb?

It can perish the world and suck in all the life from you in just a moment like a whirlpool . And now I am going to lay before you the history of it, starting from the world war to Manhattan project to the explosion.

Before I go for the history , I would like to tell that many people , ignorantly , criticize Albert Einstein for the invention of  nuclear bombs . But it is totally a false statement. Yes, there is a contact between nuclear bomb and Einstein but from other aspects.  First of all, the nuclear bomb uses Einstein’s  theory of relativity’s equation =>  E=MC^2 . The second contact is related to history , rather than science . Before the world war two , Einstein , in 1937 2^nd August , sent the president of America a letter informing that Germany had been making a nuclear bomb in secret .

And therefore started another secret project in America named Manhattan Project attempting to make another nuclear bomb .

Let’s now go to physics . By the name – Nuclear bomb , one can surely understand that the energy must come through nucleus of an atom. And one who have learnt the whole of theory of relativity and  the history of Manhattan project can be sure of it , as if without even reading it . But still let’s get back to square one . Energy In a nuclear bomb comes from the nucleus of an atom which consists of electron , proton and neutron . The first bomb that caused the explosion  in Hiroshima – Little Boy – used Uranium 235  as  the nucleus . In a uranium 235 there are 92 protons and 143 neutrons . One can surely understand that this  nucleus is large and mostly in solid form .

If we can put another neutron in this nucleus , it will be broken into two parts and there will be some many other smaller neutrons. We will also that these smaller neutrons’ mass will be smaller than the total mass of the primary neutron and the neutron (that has been put into). This mass difference comes out as the energy .

It seems like as if it is like a piece of cake , but the first work is like getting as tall as the altitude of the sky from earth . Collecting Uranium 235 is very hard as most part of the Uranium is Uranium 238 from which we can’t make nuclear bombs. It is an isotope.  Even putting the nucleus into uranium is very difficult.

We all know that when nuclear bomb explodes , it starts chain-reaction. Scientists have found out that to start the chain-reaction , we have to put the uranium together at a certain mass called the Critical Mass . If I write down the amount of Critical mass , then I may have to go to jail myself .

If you can put two parts of uranium 235 at critical mass together , then the energy shall come out . For nuclear bomb  we need Super Critical Mass .

This was the explanation of Little Boy .Now we are going to talk about the second bomb made in the Manhattan project .

Plutonium 239 was used in the second bomb . We have to give pressure to a large sphere and make a smaller super critical mass . And then the general ordinary bombs around the sphere explode  to cause a huge explosion ! And then ………BOMBA      BOOOOOOOM !!

This manhattan project was under Robert Oppenheimer , a very great scientist , who is usually credited  for the discovery of nuclear energy .

The explosions occurred in 1945 , 6th August in Hiroshima and then on the 9th August , 1945 . 

   

Information source and reference : Md. Jafar Iqbal 's book - Aro Ektukhani Biggan