Force

The presence of force on a moving charge causes an alteration in the state of a body. It influences a motion to commence, conclude, or accelerate due to the force that the universe functions concerning the progressing time scale. 

Force has enjoyed considerable attention from numerous scientists that have existed between millennia. This article is dedicated to discussing several concepts related to force from a Physics point of view. Our goal is to introduce the evolution of the concept, types of forces, and theory of their unification through this force study material.

Evolution of the concept of force

The cause of motion and direction of the free-falling body towards the earth always has interested scientists. The concept dates back to Aristotle when he gave laws of motion. He proposed that:

1. Heavier objects fell faster.

2. The objects existed in a natural state where earthly objects remained on the crust, and heavenly objects exhibited circular motion.

3. There existed a natural and violent motion.  

Moving forward in history, Archimedes studied the subject and proposed the Archimedes principle, law of the lever, Archimedes’s Catapults, and Archimedes’s Screw. Then came Ptolemaeus and Copernicus, who studied celestial bodies contributing to the subject of gravity. 

Further, the works of Kepler proved that some mysterious force attracted the heavenly bodies. Moreover, scientists like Galileo and Newton further identified the principles of gravity. Later scientists successfully proposed laws of motion and gravity, providing a clear picture of the concept. 

The subject of Physics took a huge turn with the advent of Quantum Mechanics when Einstein proposed relativity theory and discovered the Gravitational waves. On the other hand, Coulomb, Ampere, Faraday, Pauli, Hertz, Tesla, Thomson, and Maxwell lead to the development of electromagnetism.

Formula of Force

According to Newton’s Second Law of motion which states that the force applied on an object is directly proportional to the change in momentum, we get:

F ∝ dp/dt

Here, p = mv (linear momentum). On substituting the value, we get:

F ∝ d(mv)/dt

F =k mdv/dt

Here constant k = 1, therefore we have:

F =mdv/dt

Since the rate of change of velocity is equal to acceleration, we get dvdt= a

F = ma

This is the general formula of force applied on an object. The SI unit of force is named after Issac Newton.

Symbol of force: F

SI unit: Newton

General formula

F = ma, 

m= mass

a = acceleration

Dimension: MLT-2

The Four Fundamental Forces of Nature

Gravitational Force

To put it simply, the gravitational force is the attractive force that exists between objects carrying a mass. It implies that the heavier the objects are, the greater is the force. This idea was proposed by Newton, who gave the Law of Gravity:

“Bodies of masses experience a force of attraction between them. The magnitude is directly proportional to the product of their masses and inverse to the square of the distance between them.”

F = GMm/r2

Electromagnetic Force

The electromagnetic force results from two forces, namely the electric and magnetic forces. The charge creates an electric field that induces a force on a moving charged particle that enters the field region. The force can be repulsive or attractive depending on the likeness and difference of the charges, respectively. 

The magnetic component starts to exist when the charge experiences motion. The electromagnetic force thus exists when a charged particle moves such that its electric component is not cancelled. 

Strong Nuclear Force

It is a short-range force that exists within the nuclei of atoms. This type of force only exists at short distances. It implies that it will only bind the particles within a particular range.

Due to this very force nucleons exist close to each other. This force is strong enough to overcome the repulsive Coulomb force between the protons.

Weak Nuclear Force

The application of weak nuclear force is observable in radioactive decay and fusion reactions. It is a short-range force that changes the form of subatomic particles and causes them to decay. 

This force is awarded as the fueling force for the sun. The change in particles occurs when they come close to each other more than a particular range. As they cross this range, they exchange force-carrying particles called Bosons. With this exchange, they change their form.

Theory of Unification

This theory argues that everything was confined in a single mass before the big bang. Therefore, the four fundamental forces were also unified and existed as one force responsible for binding all matter as one entity; with the big bang and the formation of dimensions and universes, these forces spitted and expanded in every area and dimension.

Scientists persist in deriving evidence that results in merging these forces. To frame a mathematical conclusion, information of carrier particles demands discovery. The carrier particles of gravitational force are yet to be discovered. For this purpose, scientists such as Carlo Rovelli and Michio Kaku have been working on Quantum Gravity to determine the origin fundamentals.

Conclusion

Cause and effect have always been subjects of interest to scientists. We understand that force on a moving charge is a system responsible for changing and maintaining the states of different objects in the universe through this force study material. Throughout history, several pieces of research on forces have been made inspired by this very concept. 

The four fundamental forces of nature include gravitational force, electromagnetic force, strong nuclear force, and weak nuclear force. These forces have been studied to have existed in unification before creating the multiverse. Scientists are in search of mathematical evidence related to the concept of unification.