General Physics (1) For Engineering Textbook PDF

General Physics (1) For Engineering Textbook: Physics for Scientists and Engineers, seventh edition, Jewett / Serway Lecturer: Dr. Aljghami Issam Fawaz Final mark will be divided as follows: 10% Homework and Quiz 20% First exam. 20% Second exam....

General Physics (1) For Engineering Textbook: Physics for Scientists and Engineers, seventh edition, Jewett / Serway Lecturer: Dr. Aljghami Issam Fawaz Final mark will be divided as follows: 10% Homework and Quiz 20% First exam. 20% Second exam. 50% Final exam. Physics for Scientists and Engineers Introduction and Chapter 1 Physics  Thestudy of Physics can be divided into six main areas:  Classical mechanics, Concerning the motion of objects that are large relative to atoms and move at speeds much slower than the speed of light.  Relativity, a theory describing objects moving at any speed, even speeds approaching the speed of light.  Thermodynamics, dealing with heat, work, temperature, and the statistical behavior of systems with large numbers of particles. Physics  Thestudy of Physics can be divided into six main areas:  Electromagnetism, concerned with electricity, magnetism, and electromagnetic fields.  Optics, the study of the behavior of light and its interaction with materials.  Quantum mechanics, a collection of theories connecting the behavior of matter at the submicroscopic level to microscopic observations. Objectives of Physics  To find the limited number of fundamental laws that govern natural phenomena  To use these laws to develop theories that can predict the results of future experiments  Express the laws in the language of mathematics  Mathematics provides the bridge between theory and experiment Measurements  Used to describe natural phenomena  Needs defined standards  Characteristics of standards for measurements  Readily accessible  Possess some property that can be measured reliably  Must yield the same results when used by anyone anywhere  Cannot change with time Standards of Fundamental Quantities  Standardized systems  Agreed upon by some authority, usually a governmental body  SI – Systéme International  Agreed to in 1960 by an international committee  Main system used in this text Fundamental Quantities and Their Units Quantity SI Unit Length meter Mass kilogram Time second Temperature Kelvin Electric Current Ampere Luminous Intensity Candela Amount of Substance mole Quantities Used in Mechanics  In mechanics, three basic quantities are used  Length  Mass  Time  Will also use derived quantities  These are other quantities that can be expressed in terms of the basic quantities  Example: Area is the product of two lengths  Area is a derived quantity  Length is the fundamental quantity Length  Length is the distance between two points in space  Units  SI – meter, m  Defined in terms of a meter – the distance traveled by light in a vacuum during a given time  See Table 1.1 for some examples of lengths Mass  Units  SI – kilogram, kg  Defined in terms of a kilogram, based on a specific cylinder kept at the International Bureau of Standards  See Table 1.2 for masses of various objects Standard Kilogram Time  Units  seconds, s  Defined in terms of the oscillation of radiation from a cesium atom  See Table 1.3 for some approximate time intervals US Customary System  Still used in the US, but text will use SI Quantity Unit Length foot Mass Slug=32,2 pound Time second  T h e B ritish S y stem L en g th : 1 in ch = 2.5 4 cm F o rce: 1 p o u n d = 4.4 4 8 2 2 1 6 1 5 2 6 0 N ew to n s  F o r tim e, th e B ritish u n it is seco n d. B ritish u n its a re u sed o n ly in m ech a n ics a n d th erm o d y n a m ics. N o B ritish u n its fo r electrica l u n its.  U n it P refi x es O n ce w e h a v e d efi n ed th e fu n d a m en ta l u n its, it is ea sy to in tro d u ce la rg er a n d sm a ller u n its fo r th e sa m e p h y sica l q u a n tities. T h e n a m es o f th e a d d itio n a l u n its a re d eriv ed b y a d d in g a p refi x to th e n a m e o f th e fu n d a m en ta l u n it. F o r ex a m p le, th e p refi x “ k ilo -” a b b rev ia ted k ; th u s 1 k ilo m etre = 1 k m = 1 0 3 m eter = 1 0 3 m 1 k ilo g ra m = 1 k g = 1 0 3 g ra m s = 1 0 3 g 1 k ilo w a tt = 1 k W = 1 0 3 w a tts = 1 0 3 W  L en g th 1 n a n o m eter = 1 n m = 1 0 -9 m (a few tim es th e size o f th e la rg est a to m ) 1 m icro m eter = 1 μ m = 1 0 -6 m (size o f so m e b a cteria a n d liv in g cells) 1 m illim etre = 1 m m = 1 0 -3 m (d ia m eter o f th e p o in t o f a b a llp o in t p en ) 1 cen tim etre = 1 cm = 1 0 -2 m (d ia m eter o f y o u r litter fi n g er) 1 k ilo m etre = 1 k m = 1 0 3 m (a 1 0 -m in u te w a lk )  M a ss  1 m icro g ra m = 1 μ g = 1 0 -6 g = 1 0 -9 k g (m a ss o f a v ery sm a ll d u st p a rticle)  1 m illig ra m = 1 m g = 1 0 -3 g = 1 0 -6 k g (m a ss o f a g ra in o f sa lt)  1 g ra m = 1 g = 1 0 -3 k g (m a ss o f a p a p er clip )  T im e 1 n a n o seco n d = 1 n s = 1 0 -9 s (tim e fo r lig h t to tra v el 0.3 m ) 1 m icro seco n d = 1 μ s = 1 0 -6 s (tim e fo r a n o rb itin g sp a ce sh u ttle to tra v el 8 m m ) 1 m illiseco n d = 1 m s = 1 0 -3 s (tim e fo r so u n d to tra v el 0.3 5 m ) Prefixes, some more examples  Basic Quantities and Their Dimension  Dimensions are denoted with square brackets  Length [L]  Mass [M]  Time [T] Dimensions and Units  Each dimension can have many actual units  Table 1.5 for the dimensions and units of some derived quantities Dimensional Analysis  Technique to check the correctness of an equation or to assist in deriving an equation  Dimensions (length, mass, time, combinations) can be treated as algebraic quantities  add, subtract, multiply, divide  Both sides of equation must have the same dimensions  Any relationship can be correct only if the dimensions on both sides of the equation are the same Dimensional Analysis, example  Giventhe equation: x = ½ at 2  Check dimensions on each side: L L  2 T 2 L T  The T2’s cancel, leaving L for the dimensions of each side  The equation is dimensionally correct  There are no dimensions for the constant Dimensional Analysis to Determine a Power Law  Determine powers in a proportionality Example: find the exponents in the expression x  a t m n   You must have lengths on both sides  Acceleration has dimensions of L/T2  Time has dimensions of T m =1,n =2  Analysis gives x  at 2 Conversion of Units  When units are not consistent, you may need to convert to appropriate ones  See Appendix A for an extensive list of conversion factors  Units can be treated like algebraic quantities that can cancel each other out Conversion  Always include units for every quantity, you can carry the units through the entire calculation  Multiply original value by a ratio equal to one  Example 15.0 in ? cm  2.54 cm  15.0 in   38.1cm  1in   Note the value inside the parentheses is equal to 1 since 1 in. is defined as 2.54 cm Conversion, Examples:  5 kg / m3  ? g / cm3 v 100 km / hr ? m/s M 3 mg ? g ? g ? kg L 3 mm ? nm ? cm ? km t 3 ms ? ns ? s ? s P 3 MW ? kW ? GW ? W