PHY101 Handouts by VUBuddy

Physics-PHY101-Lecture #01 INTRODUCTION TO PHYSICS & THIS COURSE

1.1. Introduction

Welcome to Physics. We will embark on a long journey that will consist of 45 lectures. Nevertheless, I hope will find it interesting and enjoyable. As I continued to study and research in this subject my interest in this subject grew. But before we come to physics, I want to remind all students that physics is the branch of science and must be aware of the fact that our modern world is based on concepts from science, modern machines/equipment rely on science and inventions such as telephones, satellites, etc. are based on science. But in reality, science is a way of thinking that only accepts the rule of reasoning. In which the judgment of truth and falsehood is based on the sets of results from an experiment. So as mentioned earlier physics is the branch of science that is often termed as the “queen” of science and is rightly said to be the greatest science. The history of science is as old as the story of mankind. When did it start? It is probably tens of thousands of years old. Every civilization has contributed to it. It may have started from the time of Babylon, but after that, the Greeks created great perfection in it, and then Chinese, Hindu and Islamic civilizations advanced it. Physics in its present form is not that much old. It started about three and a half hundred years ago, and it was a time when a great scientific revolution took place in Europe, which is called the Scientific Revolution, and this was the time when great scientists like Newton revolutionized it which is the reason why our present-day world is so different from previous eras. Physics is related to every worldly thing (actually everything in the whole universe) with its main purpose being to fully understand the whole physical world/universe and it means that everything, no matter how big or small it is. For example, if we look at our solar system (as shown in Figure 1.1), the sun is at the center and planets revolve around it. Human beings have thought a lot over many fundamental questions like, how heat is produced in the sun and then how it reaches the Earth. Why and how does the Earth rotate around the sun? Contrary to this, in general, if anything moves it moves in a straight line but the earth continues to move around the sun in a circular path. Figure 1.1. Schematic of Solar System. Sun at the center and planets revolving around the Sun.

Atom was considered to be the smallest thing in the world making up all the matter. The atom was considered to be a basic building block but now we know that it can be further broken down as it has a center called the nucleus and electrons revolve around the nucleus as shown in Figure 1.2(a). Upon closer inspection of the nucleus Protons and neutrons can be observed. Interestingly protons and neutrons can be further subdivided into particles called quarks as shown in Figure 1.2(b).

Figure 1.2. (a) Atomic Structure showing nucleus at the center having Proton and Neutron. Electrons revolve around the nucleus. (b) Protons can be subdivided into quarks. (b) (a) So, on the one hand physics is related to the sun, the solar system, galaxies, and the universe itself, and on the other hand, it is also related to atoms and subatomic particles, and lastly all kinds of entities that come in between these two extremes. These entities can be classified as forms of matter which are as follows

1. Solids
2. Liquids
3. Gases

The first form of matter is called solids in which atoms can't move very far from each other for example table salt. The sodium atom in the salt cannot move away from the chlorine atoms. Atoms are fixed to each other and immobile as shown in Figure 1.3.

Figure 1.3. Structure of common table Salt (Sodium Chloride, NaCl)

Matter can be in a liquid state and when the substance is in the liquid state, the atoms or molecules that are there can move quite far from each other but still there is some kind of attraction among them confining them. For example, if we put water in a vessel, then this water takes the shape of the vessel and this is a characteristic of the matter when it is in a liquid state. Lastly, there is another situation in which matter can be in a gas state. Well, if the matter is in a gaseous state, then its atoms and molecules can move around freely anywhere and far away from each other. Gases like oxygen, hydrogen, and nitrogen make up our atmosphere and without oxygen, we cannot even breathe.

The purpose of this course is to introduce students to the vast subject of physics. Although even experts in the field only know a fraction of it, we will do our best to learn and gain knowledge related to physics in all 45 lectures. The main goal of this course is to teach problem-solving to