G9 Physics STB 2023 Past Paper PDF

Unit 1 Physics and Human Society Introduction You learnt about general science in lower grades. General science includes sub- Brainstorming jects like Biology, Chemistry and Physics. Therefore, in this grade level and in Questions higher grades, you will learn about each of the three s...

Unit 1 Physics and Human Society Introduction You learnt about general science in lower grades. General science includes sub- Brainstorming jects like Biology, Chemistry and Physics. Therefore, in this grade level and in Questions higher grades, you will learn about each of the three subjects and explore their t Explain science beauty. In this unit you will learn about physics and the human society. In par- and its broad cate- ticular, you will learn about definition of physics, different branches of physics, gories. relationship between physics and other fields of study, contributions of promi- t What are the nent scientists in advancing physics, and the way physics knowledge was evolving main branches of and changing in history. natural science? At the end of this unit, you should be able to: define physics in different ways; describe the different branches of physics; describe the relationships between physics and other fields of study; discuss the contributions of prominent scientists in advancing physics at different periods of time; describe how aspects of physics are used in other sciences (e.g. biology, chemistry, engineering, etc.) as well as in everyday technology; and discuss how physics knowledge was evolving and changing in history. 2 Unit 1 Physics and Human Society 1.1 Definition and Nature of Physics Exercise 1.1 t In your own At the end of this section, you should be able to: words, define what define physics in different ways. physics is. t Name other tech- Have you ever thought about some modern technological devices such as nological products computers, smart phones, tablets etc? Also think about the fact that our histor- in your locality that ical heritages such as Harar Jugol, Fasciledes Castle, the Obelisk of Axum and rely on the principle rock-hewn churches of Lalibela buildings have kept their balance and survived of physics. for hundreds of years. The working principles of all these rely on physics. The word physics is thought to have come from the Greek word phusis, mean- ing nature. Hence, physics is a branch of natural science aimed at describing the fundamental aspects of our universe. These include what things are in it, what properties of those things are noticeable, and what processes those things or their properties undergo. In simpler terms, physics attempts to describe the basic mechanisms that make our universe behave the way it does. For example, Activity 1.1 Physics enables you to understand the working principles of cars, airplanes, t By discussing in space-rockets, refrigerators, radios, televisions,etc as well as many of your groups, mention im- daily utensils and tools. portance of physics other than those Physics explains physical phenomena such as the difficulty of walking on a mentioned above. smooth plane, and why an electric fan rotates etc. t What other physi- cal phenomena may Physics helps you discover some of the unknown parts of nature and makes you understand in you familiar with the modern world. your locality using physics? Physics helps you to understand some concepts in other subjects like: t What is a physi- Biology, Chemistry, Geology, Astronomy, etc. cist? Studying physics helps you understand concepts, relationships, principles and laws of nature. A person who studies physics is called a physicist. In addi- tion to understanding the concepts, relationships, principles and laws of nature, studying physics has various career opportunities. Some of te fields in which physics is applicable include: The field of transportation The field of aviation and space science 1.2 Branches of Physics 3 The field of medicine The field of forensic and military science the field of meteorology and metrology etc Key Concept: t Physics is a 1.2 Branches of Physics branch of natu- ral science that At the end of this section, you should be able to: attempts to describe describe the different branches of physics. the basic mecha- nisms that make our As our technology evolved over the centuries, physics has expanded into universe behave the many branches. Some of the branches of physics are summarized in Table 1.1. way it does. Exercise 1.2 t List as many physical phenomena in your surroundings as you can. Describe in which branch of physics each physical phenomenon can be categorized. Key Concept: Activity 1.2 t The branches of physics include: Mechanics, Acoustics, Optics, Ther- t Discuss in groups modynamics, Electromagnetism, Nuclear Physics, etc. and list some other fields or areas of sci- ence where physics is applicable. 1.3 Related Fields to Physics At the end of the lesson, you should be able to: Key Concept: identify different general fields of physics and their applications in life; tPhysics is the discuss the relationships between physics and other sciences and fields foundation of many important scientific like transport, traffic, quality control and standards, etc. disciplines including, Chemistry, Engi- Physics is the foundation of many important scientific disciplines. Some of neering, Geology, them are discussed below. Biophysics, Geo- Chemistry: Chemistry deals with the interactions of atoms and molecules. physics, Medical Physics etc. However, it is rooted in atomic and molecular physics. 4 Unit 1 Physics and Human Society Table 1.1 Some branches of physics and their descriptions Branch Description Mechanics Mechanics is the branch of physics which deals with the motion of an object without or with the reference of force. Mechanics can be further divided into two branches namely quantum mechanics and classical mechanics. Quantum mechanics deals with the behavior of smallest particles like neutrons, protons, and electrons, while classical mechanics is the branch that deals with laws of motion of forces and physical objects. Acoustics Acoustics is the branch of physics which deals with the study of sound and its transmission, production, and effects. Optics Optics is the branch of physics which deals with the behav- ior, propagation, and properties of light. Thermodynamics Thermodynamics is the branch of physics which studies thermal energy and the transfer of heat. Electromagnetism Electromagnetism is the branch of physics which deals with the study of electromagnetic force like electric fields, light, magnetic fields, etc. There are two aspects of electromag- netism which are "electricity" and "magnetism" Nuclear physics Nuclear physics is the branch of physics which deals with the structure, properties and reactions of the nuclei of atoms. Astrophysics Astrophysics is a science that employs the methods and principles of physics in the study of astronomical objects and phenomena. Engineering: Most branches of engineering also apply physics. For exam- ple, in architecture, physics is at the heart of determining structural stability, acoustics, heating, lighting, and cooling for buildings. Geology: Parts of geology, the study of nonliving parts of Earth, rely heavily on physics; including radioactive dating, earthquake analysis, and heat transfer across Earth’s surface. Biophysics: Biophysics applies principles and methods used in physics to study biological phenomena.Physics uses mathematical laws to explain the 1.4 Historical Issues and Contributors 5 natural world, and it can be applied to biological organisms and systems to gain insight into their workings. Geophysics: Geophysics applies the principles and methods of physics to the study of the Earth Medical Physics: Diagnostics and medical therapy, such as x-rays, mag- netic resonance imaging (MRI), and ultrasonic blood flow measurements involves principles of physics. 1.4 Historical Issues and Contributors At the end of the lesson, you should be able to: recognize at least three issues and four prominent physicists with signifi- cant contributions to the development of physics; collect and use pictures and texts from a library and the internet to present prominent figures in the history of physics. Over the last few centuries, the growth of scientific knowledge has resulted in ever-increasing specialization and branching of physics into separate fields. Physics, as it developed from the renaissance to the end of the 19th century, is called classical physics. Revolutionary discoveries starting at the beginning of the 20t h century transformed physics from classical physics to modern physics. Many laws of classical physics have been modified during the 20t h century, re- sulting in dramatic changes in technology, society, and our view of the universe. Discoveries of physics find applications throughout the natural sciences and in technology. Some of the physics discoveries that changed the world are discussed below.. Isaac Newton contributions laid the foundations for classical physics/clas- sical mechanics. He contributed to the Scientific Revolution of the 16th and 17th century by formulating three laws of motion, known as NewtonâĂŹs laws of motion and showed how the principle of universal gravitation could be used to explain the behavior not only of falling bodies on the earth but also planets and other celestial bodies in the heavens. 6 Unit 1 Physics and Human Society Michael Faraday contributed a lot to the field of electromagnetism. In 1821 he succeeded in producing mechanical motion by means of a permanent magnet and an electric current. Ten years later he converted magnetic force into electrical force, thus inventing the world’s first electric generator.In general Michael Faraday changed the world with magnet. James Prescott Joule studied the nature of heat, and discovered its rela- tionship to mechanical work. This led to the law of conservation of energy. Joule’s work helped lay the foundation for the first of three laws of thermo- dynamics that describe how energy in our universe is transferred from one object to another or transformed from one form to another. Marie Curie conducted pioneering research in the field of nuclear physics, particularly on radioactivity. She is considered as the mother of modern nuclear physics. She discovered elements polonium and radium. Albert Einstein is known for developing theory of relativity. This revolution- ary theory had a profound impact on classical mechanics and the under- lying philosophy of physics. He is widely acknowledged to be one of the greatest physicists of all time. Einstein also made important contributions to the development of the theory of quantum mechanics. Exercise 1.3 t Mention some other well-known historical contributors in physics and describe their roles. Key Concept: t Revolutionary discoveries starting at the beginning of the 20th century transformed physics from classical physics to modern physics. Many laws of classical physics have been modified during the 20t h century, resulting in dramatic changes in technology, society, and our view of the universe