1. 1 Phys 1111K Spring 2005 Course Overview Dr. Perera Room: 507 Science Annex Phone: 651-2709, 3221/3222

2. 2 Introduction What is Physics ? Understanding nature Laws of Physics Wide spread impact on modern technology Every minute of your life is involved in Physics Needs and Uses Even without knowing it A Fundamental Science  Welcome to Introduction to Physics

3. 3 Main Sections Kinematics Classical Mechanics (Chs 1-10) both Transnational and Rotational Dynamics Fluid Mechanics (Ch 11) Thermodynamics (Chs 12-13) Heat Temperature

4. 4 Ch 1 Pre Requisites Co-ordinate System (Cartesian) Trigonometry Pythagorean Theorem Sin θ Cos θ Pythagorean Theorem Tan θ Algebra Quadratic Equations Powers of 10 Symbols Δx, μ, n, p

5. 5 Standards and Units CGS BritishSI Length centimeter (cm) foot (ft) meter (m) Mass gram (g) slug (sl) kilogram (kg) Timesecond (s) Why do we need standard units ? King Louis Yard Royal foot

6. 6 SI Units Le System International Units meter : Light travels in a vacuum in time of 1/ 299792458 seconds kilogram : Standard cylinder of Pl-Iridium alloy at room temperature second :Cs-133 atomic clock – time for 9192631770 wave cycles to occur

7. 7 Conversion of Units 1 meter = 100 centimeter = 1000 millimeter (mm) 10 3 meter = 1000 meters = 1 kilometer 0.001 meter = 10 -3 meter = 1 millimeter 3.281 feet = 1 meter 5280 feet = 1 mile 3600 seconds = 1 hour 0.65 miles / hour = 95 feet / second = 29 meters / second

8. 8 Significant Figures Keep the same number of significant figures in the answer as in the least accurate number 3.5 × 10.6 = 37 (not 37.1) 0 ± 0.1 0 ± 0.1 35 39 Uncertainty : Quality of the apparatus Skill of the experimenter Number of measurements

9. 9 Dimensional Analysis Distance -[L] Mass -[M] Time -[T] Check whether an equation is mathematically correct Find an unknown exponent

10. 10 Vectors and Scalars Addition and subtraction Multiplying by a number Components Vector addition by Components Vector addition by Graphing

11. 11 Vector Addition (Due East) Resultant Displacement R = A+ B Due East and then Due north R = A +B 5 = 4 +3 ? Find Theta

12. 12 What if Vectors are not Perpendicular ? Can we say R = A +B ? But Pythagorean Theorem valid ? Graphical Technique A = 275 m, B =125 m Scale 1 cm = 10 m R = 228 m

13. 13 Vector Components r = X + Y r  A, X  A x Y  A Y

14. 14 Different Axes Vector Components depend on the orientation of the axes Scalar components (With positive or negative sign )

15. 15 Adding Vectors Using Components C = A +B, C = C x + C Y A = A x +A y C X = B = B x + B y C Y =

16. 16 Example 8 A B R x y A+B=R A=A x +A y B=B x +B y Note B y is in negative direction. A B R x y AXAX AyAy 20 A B R x y AXAX AyAy BXBX ByBy 35

17. 17 Example 8 (continued) x componenty component A Asin20=145sin20=49.6Acos20=145cos20=136.3 B Bcos35=105cos35=86.0-Bsin35=-105sin35=-60.2 R A x +B x =135.6A Y +B Y =76.1

18. 18 Example 8 (continued)