Physics Introduction (PDF)

LESSON 1: Introduction to Physics Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023] ...

LESSON 1: Introduction to Physics Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023]  Outline: Physics Defined Main Categories of Physics Some of the famous contributors in the study of Physics Standard Units Measurement Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2022]  WHAT IS PHYSICS ? Physics is a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. More broadly, it is the study of nature in an attempt to understand how the universe behaves.  WHAT IS PHYSICS ? Physics aims to describe the function of everything around us, from the movement of tiny charged particles to the motion of people, cars, and spaceships. In fact, almost everything around us can be described quite accurately by the laws of physics. MODEL, THEORY, & LAW A model is a representation of something that is often too difficult (or impossible) to display directly. While a model is justified with experimental proof, it is only accurate under limited situations. MODEL, THEORY, & LAW MODEL, THEORY, & LAW The law of gravity states that every time you drop an apple, it will fall to the ground. The theory of gravity is the explanation as to why the apple falls to the ground. A law is an observation. A theory is an explanation. PHYISICS  Theoretical Physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. Einstein-Rosen Bridge (Wormhole) Big Bang Theory Theory of Relativity  Experimental Physics Experimental physics uses methods in observations and experiments, as well as tools in experimentations to study these physical phenomena. It is also involved in testing the predictions generated by theoretical physics by devising appropriate experiments. Faraday Cage Cavendish Experiment Applied Physics Applied physics is the application of physical theories to problem-solving. It is the use of theoretical knowledge of the properties of physical bodies with the intention of achieving a particular technological or practical goal. Rockets Ship Buoyancy Main Categories of Physics Mechanics - branch of Physics concerned with the motion of bodies under the action of forces, including the special case in which a body remains at rest. Electromagnetism - branch of Physics that deals with the electromagnetic force that occurs between electrically charged particles. Optics - branch of Physics that studies electromagnetic radiation (for example, light and infrared radiation), its interactions with matter, and instruments used to gather information due to these interactions. Optics includes the study of sight. Acoustics - branch of Physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. Thermodynamics - branch of Physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. Some Contributors in the Study of Physics Galileo Galilei (1564- 1642) Performed fundamental observations, experiments, and mathematical analyses in astronomy and physics; Of all of his telescope discoveries, he is perhaps most known for his discovery of the four most massive moons of Jupiter discovered mountains and craters on the moon, and the phases of Venus William Gilbert (1544- 1603) He discovered that our planet has two magnetic poles; he defined these poles correctly and established that the earth behaves like a giant magnet Benjamin Franklin (1706-1790) characterized two kinds of electric charge, which he named ``positive'' and ``negative‘’ Invented the “The Lightning Rod” He discovered that when a pointed object is held towards a charged object, it draws electricity from the object. Sir Isaac Newton (1643-1727) developed theories of gravitation and mechanics, and invented differential calculus Known for his Laws of Motion Michael Faraday (1791-1867) discovered electromagnetic induction and devised first electrical transformer In 1821, he invented the electric motor, and in 1831 he made the first dynamo, known as the Faraday disc, a forerunner of today's electrical generator, when he discovered the induction of electric currents. Henry Cavendish (1731-1810) discovered and studied hydrogen; first to measure Newton's gravitational constant; calculated mass and mean density of Earth Nikola Tesla (1857- 1943 Tesla developed the alternating-current power system that provides electricity for homes and buildings. He also pioneered the field of radio communication and was granted more than 100 U.S. patents. Max Planck(1858- 1947) theoretical physicist who discovered the quantum of action, now known as Planck's constant, h, in 1900. Planck called the packets of energy “quanta” and he was able to determine that the energy of each quantum is equal to the frequency of the radiation multiplied by a universal constant that he derived, now known as Planck's constant. The value of Planck's constant is 6.62607015 × 10−34 joule-second. Albert Einstein (1879- 1955) explained Brownian motion and photoelectric effect; contributed to theory of atomic spectra; Famous for devising his theory of relativity, which revolutionized our understanding of space, time, gravity, and the universe. Physical Quantities and Units of Measurement 7 Fundamental Physical Length - can be Mass – a Time - the Temperature - defined as a quantitative duration of an measure of measurement of measure of inertia; event hotness or the physical a fundamental coldness quantity of property of all distance. matter. Quantities Amount of Substance - is a Electric Current - the Luminous Intensity - measure of the number of rate at which the quantity of visible specified elementary entities. electrons flow past a light that is emitted An elementary entity may be point in a complete in unit time per unit an atom, a molecule, an ion, an electron, any other particle electrical circuit. solid angle. or specified group of particles. Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2022] International French - Système Standard of Units International (S.I. units) d’Unités Derived the seven basic units of Physics Meter The meter (m) is the fundamental unit of length. It is defined as the distance traveled by light in a vacuum during a specific time interval. The meter is widely used to measure distances, dimensions, and sizes of objects.  Kilogram The kilogram (kg) is the fundamental unit of mass. It is defined as the mass of the International Prototype of the Kilogram, a platinum- iridium cylinder kept at the International Bureau of Weights and Measures in France. The kilogram is used to measure the amount of matter in an object. Second The second is the fundamental unit of time. It is defined as the duration of 9,192,631,770 cycles of the radiation corresponding to the transition between two energy levels of a cesium- 133 atom. The second is used to measure time intervals, durations, and frequencies.  Kelvin The kelvin is the fundamental unit of temperature. It is defined based on the properties of matter and the behavior of gases. The kelvin scale is an absolute temperature scale with zero representing absolute zero, the lowest possible temperature. The kelvin is used to measure temperature in scientific and engineering applications. Mole The mole is the fundamental unit of amount of substance. It is defined as the amount of a substance that contains as many elementary entities (atoms, molecules, ions, etc.) as there are atoms in 0.012 kilograms of carbon-12. Candela The candela is the fundamental unit of luminous intensity. It is defined as the luminous intensity, in a given direction, of a source that emits monochromatic radiation of a specific frequency with a specific radiant intensity. The candela is used to measure the brightness or intensity of light.  Physical Quantity S.I. Unit Abbreviation Length Meter m Mass Kilogram kg S.I Units of Time Second s Physical Quantities Temperature Kelvin K Amount of Substance Mole mol Electric Current Ampere A Luminous Intensity Candela cd Unit Prefixes Examples: 1 ms = 1 x 10-3 s 1 MHz = 1 x 106 Hz 4 MVolts = 4 x 106 Volts 7 nA = 7 x 10-9 A  Useful Unit Conversions 1 minute = 60 seconds 1 foot = 0.3048 meters 1 mile = 1609.344 meters = 1.60934 kilometers 1 deg. Celsius = 274.15 Kelvins 1 kilogram = 2.205 pounds (lbs) Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023]  Useful Unit Conversions 1 BTU = 1054J 1 cal = 4.184J 1 dyne =10-5 N 1 lb-f = 4.448 N 1 amu = 1.6606 x 10-27 kg Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023]  Useful Unit Conversions 1 horsepower (hp) = 746 Watts (W) 1 Angstrom (Å) = 10-10 m 1 light year = 9.461 x 1015 m Tkelvin= Tcelsius+273.15 TCelsius= (5/9)(Tfarenheit-32) Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023] Conversion of Units: Examples Convert 7 miles/hour to km/s DEFGH M.NOPQR SEFJDGTGLH M IJKL 7 𝑥 𝑥 IJKL M DEFG QNOO HGUJVWH = 3.13 x 10-3 km/s Conversion of Units: Examples Convert 8000 nanometers to micrometers M X MODE D MYD 8000 𝑛𝑚 𝑥 𝑥 M VD M X MODF D = 8 𝜇m Conversion of Units: Examples Convert 7400 kP to MP MOOO Z M[Z 7400 𝑘𝑃 𝑥 𝑥 M SZ M X MOF Z = 7.4 MP Conversion of Units: Examples Convert 45 in2 to ft2 E FG D 45 𝑖𝑛D 𝑥 ED HI EFG ! 45 𝑖𝑛D 𝑥 EJJ HI! =0.3125 ft2 More Examples Example 1. The mass of an electron is 9.1093837 × 10-31 kilograms. Convert this mass into milligrams (mg). # "#$ 1 × 10 𝑔 1 𝑚𝑔 9.1093837 × 10 𝑘𝑔 × × 1 𝑘𝑔 1 × 10"# 𝑔 = 𝟗. 𝟏𝟎𝟗𝟑𝟖𝟑𝟕 × 𝟏𝟎"𝟐𝟓 𝒎𝒈 Example 2. The world land speed record is 763.0 mi/h, set on October 15, 1997, by Andy Green in the jet-engine car Thrust SSC. Express this speed in meters per second. We need to convert the units of a speed from mi/h to m/s. We must therefore find unit multipliers that relate (i) miles to meters and (ii) hours to seconds. 𝑚𝑖 𝑚𝑖 1.609 𝑘𝑚 1000 𝑚 1ℎ 763.0 = 763.0 ℎ ℎ 1 𝑚𝑖 1 𝑘𝑚 3600 𝑠 = 𝟑𝟒𝟏. 𝟎 𝒎/𝒔 Example 3. The world’s largest cut diamond is the First Star of Africa (mounted in the British Royal Sceptre and kept in the Tower of London). Its volume is 1.84 cubic inches. What is its volume in cubic centimeters? In cubic meters? (1)Conversion to cubic centimeters (cm3) (2)Conversion to cubic meters (m3) ! 2.54 𝑐𝑚 1.84 𝑖𝑛! = 1.84 𝑖𝑛! 1 𝑖𝑛. 16.39 𝑐𝑚! = 1.84 𝑖𝑛! 1 𝑖𝑛! = 𝟑𝟎. 𝟏𝟔 𝒄𝒎𝟑 ! ! ! 1𝑚 30.16 𝑐𝑚 = 30.16 𝑐𝑚 100 𝑐𝑚 1 𝑚! = 30.16 𝑐𝑚! 1000000 𝑐𝑚! = 𝟑𝟎. 𝟎𝟐 × 𝟏𝟎#𝟓 𝒎𝟑 Example 4. The element oxygen has 16 atomic mass units. Convert this into kilograms. 1.6606×10"RS 𝑘𝑔 16 𝑎𝑚𝑢 × = 𝟐. 𝟔𝟓𝟔𝟗𝟔×𝟏𝟎"𝟐𝟔 𝒌𝒈 1 𝑎𝑚𝑢 Example 5. Alpha Centauri is a star system located in the constellation of Centaurus, and it is the closest star system to our Solar System. In terms of distance, Alpha Centauri is approximately 4.37 light-years away from Earth. Convert this distance to gigameters (Gm). 9.461×10$T 𝑚 1𝐺𝑚 4.37 𝑙𝑖𝑔ℎ𝑡 𝑦𝑒𝑎𝑟𝑠 × × U = 41,344,570 𝐺𝑚 1 𝑙𝑖𝑔ℎ𝑡 𝑦𝑒𝑎𝑟 1 × 10 𝑚  END OF MODULE 1 Prepared by: Engr. Charles G. Lim [DHVSU-CEA, 2023]