1. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. Chapter 1. Physics and Measurement The universe we live in is one of change and motion. Although we all have intuition about motion, based on our experiences, some of the important aspects of motion turn out to be rather subtle. TO SAY THE LEAST!! Chapter Goals: to introduce the fundamental concepts of motion as a measurable phenomenon, using ideas of length and time to introduce the concept (not needed yet) of mass to get warmed up to the mathematical rules of the game to remind ourselves of the metric system (Système Internationale), metric prefixes, and scientific notation

2. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. Translational Motion Circular Motion Projectile Motion Rotational Motion

3. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. L is measured in m(eter) [ft, mile, in, ly] let x be a position of a point object that can move only in one dimension [different meaning of dimension]: 1d motion the units of x are denoted [|x|] = m note the different fonts 1 m := distance traveled by light in vacuum in 1/299,792,458.0 s(econd) begs the question: what is a s? long ago, was a French platinum bar’s length then it was1,650,763.73 wavelengths of Cs light cm, km, , nm,... Dimensions: length L

4. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. a metric prefix is one letter that corresponds to multiplication of the unit by a power of 10 sometimes capitalized, sometimes greek usually but not always by a power of 1000 k = kilo = 1000 = 10 3 ; M = mega = 10 6 m = milli = 1/1000 = 10 –3 ;  = micro = 10 –6 c = centi = 1/100 = 10 –2 ; cc = cm 3 ≠ c(m 3 )!! don’t forget that each power of a unit needs to be converted!! example: 1 m 3 = 1 m 3 (100 cm/m) 3 = 1,000,000 cc we have injected the number 1 in the conversion, since 100 cm = 1 m so 1 = 100 cm/m Metric Prefixes & Conversion

5. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. Prefixes, cont. Section 1.1

6. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. A grab-bag of mathematical considerations if two things in an expression are added or subtracted, they are called terms and their dimensions must agree you must make their units agree too when it comes to putting in actual numbers the result will have the same units if two things in an expression are multiplied or divided, they are called factors and their dimensions may differ the result will have units that obey the same algebra of multiplication/division in complicated unit algebra, whatever is on the top of the top, and the bottom of the bottom, is actually on the top whatever is on the bottom of the top, or the bottom of the top, is actually on the bottom

7. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. handy for writing very small (close to zero or >1) write it as some number between 1 and 10, times a power of 10, by moving the decimal point that many times to the L or R example: c = 299,792,458.0 m/s = speed of light to 10 significant figures jobs: round it off to 5 sig figs and express in sci not move decimal point 8 places to L: c = 2.99… x10 8 m/s round off: 6 th sig fig is 0 < 2 ≤ 5: c = 2.9979 x10 8 m/s note: if rounded off to 4 sig figs: c = 2.998 x10 8 m/s note: if rounded off to 3 sig figs: c = 3.00 x10 8 m/s Scientific Notation and ‘Accuracy’ I

8. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. example: mass of the electron is m = 9.11 x10 –31 kg [begs the question: what is a g(ram)?] m =.000 000 000 000 000 000 000 000 000 000 911 kg 0.00000029042 has 5 sig figs 45,700 is probably 3 sig figs but might be 4 or even 5.5700 is definitely 4 sig figs, while.57 is 2 sig figs 3.0000087800 has 11 sig figs in this course, 3 sig figs is plenty! The percentage accuracy is a different thing….11 is accurate to 2 sig figs, and to about 10% accuracy.98 is accurate to 2 sig figs, and to about 1% accuracy!! Scientific Notation and ‘Accuracy’ II

9. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. T is measured in s(econd) [hr, day, yr, ns] let t be the time at which some event occurs the units of t are denoted [|t|] = s 1 s := 9,192,631,770 times the period of vibration of Cs atom’s radiation [9 or 10 sig fig] 1.00 day = (1.00 day)(24.0hr/day)(60.0min/hr)(60.0s/min) = 86,400 s [3 sig figs] Dimensions: time T Dimensions: mass M M is measured in k(ilo)g(ram) [g, slug] let m be the amount of matter in some object the units of m are denoted [|m|] = kg 1 kg := the amount of stuff in a French Pt-Ir cylinder

10. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley. example: area of a circle is A =  r 2 where  = 3.14159 and r is the radius of the circle so since [|r|] = m and [|    = m  Example: mass density of some object of mass m and volume V is  := m/V so since [|m|] = kg and [|V|] = m 3  [|  |] = kg/m 3 sometimes particular combinations get named: 1 N(ewton) = 1 kg-m/s 2 and is capitalized in homage 1 Pa(scal) = 1 N/m 2 = 1 kg/m-s 2 In all there are 7 fundamental dimensions [A(mpère) for electromagnetism; K(elvin) for thermal physics; c(an)d(ela) for illumination physics; mole for counting large numbers of things in chemistry] Derived Quantities