Chapter 1 Lecture notes by tang fu

PHY-121: Univ Physics I: Mechanics INSTRUCTOR: Dr. Fu Tang OFFICE: PSF-419 Email: ftang7@asu.edu OFFICE HOURS: T & Th 12:00-1:30 pm 22 % Final exam 48 % Midterm exams (best 4of 5) 10 % Quizzes in Recitations (best 5 of 6) 5% Clicker 15 % Homework     48-58% D 70-74% B- 85-89% A-     59-64% C 75-79% B 90-95% A <48% E 65-69% C+ 80-84% B+ >95% A+ Chapter 1 Units, Physical Quantities, and Vectors Goals for Chapter 1 To know the physical units To understand and use significant figures To manipulate vector components and add vectors To prepare vectors using unit vector notation To use and understand scalar products To use and understand vector products Units & significant figures Reading assignments: Page 4-11 Vectors?Figures 1.9?1.10 Vectors show magnitude and direction, drawn as a ray. (a) Vector addition?Figures 1.11?1.12 Vectors may be added graphically, ?head to tail.? Vector additional II?Figure 1.13 Components of vectors?Figure 1.17 Manipulating vectors graphically is insightful but difficult when striving for numeric accuracy. Vector components provide a numeric method of representation. Any vector is built from an x component and a y component. Any vector may be ?decomposed? into its x component using Acos ? and its y component using Asin ? (where ? is the angle the vector sweeps out from 0°). (a) (b) Components of vectors II?Figure 1.18 (a) (b) Finding components?Figure 1.19 Refer to worked Example 1.6. (Page 16) D = 3.00 m, ? = 45? E = 4.50 m, ? = 37? Vector component ? Calculations using components?Figures 1.20?1.21 Calculate the vector sum of two or more vectors Unit vectors?Figures 1.23?1.24 Assume vectors of magnitude 1 with no units exist in each of the three standard dimensions. The x direction is termed , the y direction is termed , and the z direction, . A vector is subsequently described by a scalar times each component. The scalar product?Figures 1.25?1.26 Also termed the ?dot product.? The scalar product II?Figures 1.27?1.28 Refer to Examples 1.11. (Page 23) Angle between two vectors ? Also termed the ?cross product.?: Magnitude: The vector product The vector product II?Figure 1.32 Refer to Example 1.12. (Page 26) A=6, B=4 Cross product?