THE FUNDAMENTAL FORCES OF NATURE (Part-1)

The force

In the mid 1687, Sir Isaac Newton introduced the three laws of motion in his book “PHILOSOPHIAE NATURALIS PRINCIPIA MATHEMATICA” Or, simply “PRINCIPIA”.

Sir Issac Newton & Principia

Though before him; people knew about force and familiar with it but, Newton gave it a firm foundation.

The great physicist and mathematician the world has ever known; defined the force quantitatively and qualitatively as well.

Though almost all of us read these three laws in our school days but, most of us only remember the third one.

Well let me remind you the other two

The three laws are as follows-

       The first law gives a qualitative definition of force which is as follows -:
“A body at rest continues to be at rest and a body at motion continues to be in  motion; without the application of an external force”.

            Well this is all about the quality of the force.  For example – A ball rolling on a floor stops after sometime; this is because of the frictional force which acts between the floor surface and the ball surface. Therefore, friction acts as an external force here.

The second law gives the quantitative definition of force. Basically it says the force is mass time acceleration.

For example – If you throw a ball, towards a wall, weighing 5 kg accelerates at 2 M/s² then, it will impart a force of 10 newtons on the wall.

The third law of motion is known to almost everyone, i.e.

“Every action has an equal and opposite reaction”

Well this can be understood by various phenomena like- Recoil of gun etc.

Apart from all these, in our day to day life we unknowingly interact with different kinds of force and the first one on this list is “Gravity”

From the very beginning of our life we started struggling with this force. When we all are toddlers, we fell many times on ground in our struggle to stand. This force which keeps our foot on the ground and we have spent a lot of energy and fuel in order to get rid of it and go to space.

Well apart from gravity, we also interact with other forces like-:

1. Frictional force
2. Tensile force
3. Compression force
4. Pushing & Pulling
5. Centrifugal force
6. Air resistance force
7. Applied force
8. Normal force
9. Centripetal force
10. Magnetic force

                   And the list goes on.

Well then how many forces are there in the universe?????

Don’t be surprise; but, there are only four forces in the nature.

Yes, you read it correct. Only four forces govern the whole universe.

All these forces that we read till now are just the components of these four fundamental forces and nothing else.

The four fundamental forces of nature are as follows-:

1. Electro-magnetic force
2. Nuclear strong force
3. Nuclear weak force
4. Gravitational force

Four fundamental forces of nature

We will discuss all these forces one by one.

You may notice one thing here that, I have written the gravitational force at last (despite of the fact that, it’s a   very familiar & important force).Actually there is a reason behind this and we will discuss that in the end of this chapter.

Before knowing the forces we must know some basics like

What causes the force?

I mean why two bodies feel the attraction or repulsion at all, i.e, why our body hairs got attracted towards the plastic chair and why the apple fell on the ground? OK, there is a force between the two objects but, what causes the force after all?

Why Science has only four forces?

                Why not three or, five or anything else. I mean what is the problem if we have more force?

Let’s explore….

Here is the answer for the first question-

Physicist were discovered some fundamental particles known as “BOSONS” which is responsible for the force between the two objects.

For instance – Take the example of an iron needle and magnet. The magnet and the needle attracted towards each other because of the transfer of a certain type of boson between them. 

In this case the boson is called as “Photon”. More is the boson transfer, stronger is the force.

This implies the more nearer the magnet and needle is ; more is the number of photon transfer between then and more stronger is the force and similarly as the distance between these two objects increases ; the photon transfer decreases too and the force between the objects became weaker.

These “Bosons” or, more specifically “Gauge bosons” are therefore called as “Force carrying particles”

Each fundamental force has its own kind of bosons. They are as follows-

1. Photons ------------- gauge boson of electromagnetic force
2. Gluons --------------- gauge boson of strong nuclear force
3. W and Z -------------- gauge boson of weak nuclear force
4. Graviton --------------gauge boson of gravitational force (Not found yet; only theorized)

Read more-:Part-2

Thank you
Quantum X