Reason Of Normal contact Force w.r.t. Quantum Physics

The normal force is not really due to any of the four forces of nature. The forces of nature are not all the forces in the macroscopic sense, they are just the fundamental bosonic particles in a modern quantum field theory description.

The normal force is due to the Pauli exclusion principle almost exclusively. 

 This is because electrons have the property that two electrons cannot be in the same quantum state. Two electrons can't be at exactly the same point.

But you might be thinking, "two-point particles in three dimensions can't ever be at the same point, it's infinitely improbable!" In quantum mechanics, the particles are spread out in a wavefunction, and the condition that they can't be at the same point means that wherever their spread-out-ness overlaps, the wavefunction is zero. The wavefunction is in 6 dimensions for 2 particles, so it is hard to visualize, but the zeros appear on the diagonal part, where the two positions for the particle coincide.

When you bring two objects to touch, the electron wavefunctions are squeezed together, and the average scale of variation increases slightly, because of the exclusion. The rate of change of the wavefunction is the momentum of the electron, and as you push them closer, it costs energy. This is the source of the normal force. It would not exist if electrons were elementary bosons.

Use of ROTOR present on the Tail of helicopter(An awesome example of Angular Momentum)

Helicopter p.c.:-Google 

Helicopters have a tail rotor or a second main rotor spinning in opposite direction(e.g. Chinook Helicopter) because otherwise along with the primary rotor the body would counterrotate with the primary rotor to give a

 total angular momentum = 0. 

This is the reason when u take a toy helicopter with no tail rotor then u will observe that when u fly that helicopter up then along with its flight the body of the helicopter also counters rotate w.r.t. the primary rotor to nullify the total angular momentum. But the presence of a tail rotor, the thrust produced by tail rotor compensates for the rotation of the body in the opposite direction(torque). As shown in the above diagram

Birthday of Integration Guru/ Mathematician (Leibnitz)

Happy Birthday

Gottfried Wilhelm (von) Leibniz(1st July 1646 -  14 November 1716)

Gottfried Wilhelm Leibniz was a German polymath and philosopher who occupies a prominent place in the history of mathematics and the history of philosophy, having developed differential and integral calculus independently of Isaac Newton

 

Leibniz was born into a pious Lutheran family near the end of the Thirty Years’ War, which had laid Germany in ruins. As a child, he was educated in the Nicolai School but was largely self-taught in the library of his father, who had died in 1652. At Easter time in 1661, he entered the University of Leipzig as a law student; there he came into contact with the thought of men who had revolutionized science and philosophy—men such as Galileo, Francis Bacon, Thomas Hobbes, and René Descartes. Leibniz dreamed of reconciling—a verb that he did not hesitate to use time and again throughout his career—these modern thinkers with the Aristotle of the Scholastics. His baccalaureate thesis, De Principio Individui (“On the Principle of the Individual”), which appeared in May 1663, was inspired partly by Lutheran nominalism (the theory that universals have no reality but are mere names) and emphasized the existential value of the individual, who is not to be explained either by matter alone or by form alone but rather by his whole being (entitate tota). This notion was the first germ of the future “monad.” In 1666 he wrote De Arte Combinatoria (“On the Art of Combination”), in which he formulated a model that is the theoretical ancestor of some modern computers: all reasoning, all discovery, verbal or not, is reducible to an ordered combination of elements, such as numbers, words, sounds, or colours.

I have provided very minor information on Sir Leibnitz because if i will publish his biography then it will become a novel and i know my viewers are very intelligent they can surf through the internet and can find a lot more information than what i have given.