Umm Al-Qura University Dr. Abdulsalam Ali. Physics 101. Lecture 1. Lecturer: Dr. Abdulsalam Ali Soud

Transcription

1 Physics 101 Lecture 1 Lecturer: Dr. Abdulsalam Ali Soud

2 Course Text Book Course Text Book Physics 4 th By James S. Walker

3 COURSE SYLLABUS Week No Contents Introduction to Physics 1- Unit of Length, Mass, Time 2- Dimensional analysis. 3- significant Figures 4- Converting Units Vectors in physics. 1- Scalar & Vectors 2- Vector Addition 3-Components Of vectors 4- Unit Vector 5- Products of vector One dimensional Kinematics Newton s laws of motion Work and Kinetic Energy

4 COURSE SYLLABUS Week No Contents Waves and Sounds 1- Types of waves 2- Waves on a string. 3- Harmonic wave Function 4- Sound Waves, Sound intensity 5- Superposition and Interference 6- standing waves Mechanics of Fluid. 1- Density, Pressure 2- Static Equilibrium In fluids 3- Archimedes Principle and Buoyancy 4- Fluid Flow and Continuity 5- Bernoulli s Equation Mid Term Exam

5 COURSE SYLLABUS Week No Contents Temperature and Heat 1- Zeroth Law of Thermodynamics 2- Temperature scale. 3- Heat and mechanical work 4- Specific Heat 5- Conduction, Convection, and Radiation Geometrical Optics 1- The Propagation of Electromagnetic Waves 2- The EM Spectrum 3- The Reflection of Light 4- Spherical Mirrors 5- Ray Tracing For lenses 6- Thin Lenses Equation Final Exam

6 Ch1: introduction to physics What is physics: Is the study of the fundamental laws of nature. these laws can be expressed as mathematical equations. Science of measurements and experimental. Physicist ( scientist who studies Physics ) observe the phenomena of nature and try to find patterns and principles that relate these phenomena. Physics is the science of measurements

7 1-2 Units of length, mass, and time Physical quantities 1. Basic 2. Derived Basic physical quantities In mechanics Length (L), Mass (M), Time (T).

8 1-2 Units of Length, Mass, and Time Unit Systems: Two systems of units are widely used in the world. 1. SI ( International System of Units) or (mks system) Meter, Kilogram, Second. 2. British System slug (~ kg) or Pound - mass (lb) = kilogram, Foot (30.48 cm), second,

9 1-2 Units of Length, Mass, and Time into the International System of Units (SI). There are seven basic quantities.

10 Unit of The Length. Length: the meter (m) Was: one ten-millionth of the distance from the North Pole to the equator. Now: the distance traveled by light in a vacuum in 1/299,792,458 of a second.

11 Unit of The Length.

12 Unit of The Mass. Mass: the kilogram (kg) One kilogram is the mass of a particular platinum-iridium (Pt Ir) cylinder kept at the International Bureau of Weights and Standards, France.

13 Unit of The Mass.

14 Unit of The Time Time: the second (s) One second is the time required for a cesium(cs)-133 atom to undergo 9,192,631,770 vibrations. An atomic Clock

15 Unit of The Time

16 1-2 Units of Length, Mass, and Time The standard Prefixes Standard prefixes are used to designate common multiples in powers of ten angstrom = 1 10 meter

17 1-2 Units of Length, Mass, and Time Examples: a typical bacterium is about 5 micrometers ( or microns ) in length. Give this length in meters and kilometers. Solution: m 5 µ = µ 6 m

18 1-3 Dimensional Analysis The dimension in physics refer to the type of quantity in question regardless of the unit used in the measurement. Any valid physical formula must be dimensionally consistent each term must have the same dimensions This type of calculation with dimensions is ( dimensional analysis)

19 1-3 Dimensional Analysis Show that v = v o + at is dimensionally constant where v and vo are velocities and is acceleration and t is time. Solution: v L T v = o L T = at 2 Therefore the expression is dimensionally constant a L L = T = T T

20 1-3 Dimensional Analysis

21 1-4 Significant Figures. accuracy of measurements is limited significant figures: the number of digits in a measurement that are known with certainty plus the first digit that is uncertain Rules for the number of significant figures : 1. All nonzero digits are significant: g has 4 significant figures, 1.2 g has 2 significant figures.

22 1-4 Significant Figures. 2. Zeroes between nonzero digits are significant: 1002 kg has 4 significant figures, 3.07 ml has 3 significant figures. 3. zeros to the left of the first nonzero digits are not significant ( place holders ): m has only 1 significant figure, g has 2 significant figures.

23 1-4 Significant Figures. 4. Zeros that are at the end of a number and also to the right of decimal are significant ml has 3 significant figures, 0.20 g has 2 significant figures. 5. When a number ends in zeroes and also to the lift of a decimal point, the zeroes are not necessarily significant: 190 miles may be 2 or 3 significant figures, 50,600 calories may be 3, 4, or 5 significant figures.

24 1-4 Significant Figures. This ambiguity can be avoided by the use of scientific notation m (3 significant figures) g (4 significant figures), or calories (5 significant figures). Rules for mathematical operations: number of significant figures after multiplication or division is the number of significant figures in the least-known quantity.

25 1-4 Significant Figures. Example: A tortoise travels at 2.51 cm/s for s. How far does the tortoise go? Answer: 2.51 cm/s s = 30.7 cm (three significant figures)

26 1-4 Significant Figures.

27 1-4 Significant Figures. The number of decimal places after addition or subtraction is equal to the smallest number of decimal places in any of individual term. Examples: = 20.0 ( Rounding off to one place ) =115.9

28 1-5 Converting Units Converting feet to meters: 1 m = ft (this is a conversion factor) Or: (1 m / ft ) = ft (1 m / ft) = 96.3 m Note that the units cancel properly this is the key to using the conversion factor correctly! Some conversion factors 1 mile (mi) = kilometers (km) 1 yard (yd) = 3 feet (ft) 1 foot (ft) = centimeter (cm) 1 inch ( ) = 2.54 centimeter (cm) 1 Pound - mass (lb) = kilogram (kg)

29 1-5 Converting Units