# What is physics? Basic and fundamental physics concepts

### What is physics?

Physics is defined as the scientific study of matter and the movement of matter through the space and time of the universe. Physics also explains the interaction of matter in our universe.

In this article, we would look into the 4 basic and fundamental physics concepts that will help students to better understand this subject. These are:

#### 1. The Laws of Motion (Classical Mechanics)

You may have heard the story of Sir Isaac Newton sitting under an apple tree and formulating the basic laws of motion. Although this story of Newton sitting under an apple tree isn't exactly true, Sir Isaac Newton did make and explained the three fundamental laws of classical mechanics, also referred to as Newton's laws of motion. They are stated thus:

• An object at rest will continue in its state of rest; while an object in uniform motion will continue in a straight line, unless an external force acts on it.

Newton's First Law of Motion.

• The rate of change of momemtum is proportional to the applied force and will take place in the direction of that force.

Newton's Second Law of Motion.

• To every action, there is an equal and opposite reaction.

Newton's Third Law of Motion.

If we looked closely into these laws, we will see that they apply to our everyday life. For instance:

• when a tennis ball is put on a flat surface, the ball remains still unless someone touches it (or an external force acts upon it).
• On a hilly surface, gravity acts upon an object and pulls it downhill continuously, unless an opposite force (greater than gravity itself) acts against gravity.
• Plase read on gravity here.

• Finally, if we hit our head against a wall, we will feel some pain. This is so because in return, the wall exerts an equal and opposite force upon our head.

#### 2. Electromagnetism

Electromagnetism refers to the forces generated by electrons found in certain atoms. For instance, magnets have electrons that are configured in such a way that they exert force on other charged electrons.

The very reason why a magnet will attract a nail and not a paper is based on the fact that magnets exert energy on other charged particles. In this case, the particles found around the nail exists as charged particles.

We use the term photons to describe the force carried by an electromagnetic field.

Electromagnetic radiation attributes to much of our daily lives. They include visible light, radio waves, x rays, and so on. Meanwhile, understand that electromagnetic forces have the capacity to generate charges and electricity. In fact, we may have experienced this process as kids perhaps when a paper is used to attract things.

#### 3. Relativity

The work of Albert Einstein opened up the theory of special relativity after his discovery that the speed of light in a vacuum does not depend on the motion of all observers. General relativity is often described with the analogy of a moving car. It was expanded upon in the early 1900s when Albert Einstein created special relativity.

#### 4. Thermodynamics

The study of thermodynamics revolves around the relationship between heat, temperature, energy and mechanical work. These can be summarised under the four laws of Thermodynamics (numbered zero through three).

Below are the four laws of thermodynamics:

• Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

• 1st law of thermodynamics – Energy can neither be created nor destroyed but can be changed from one form to another.

• 2nd law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

• 3rd law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum. 