1. Physics 111 Honors Classical Mechanics Prof. Haimin Wang haimin@flare.njit.edu http://solar.njit.edu/~haimin

2. My Research: Solar Physics Instrumentation Magnetic Fields and Solar Activity

3. Week 1  Chapter 1 Sections 1–6 –Measurement –International System of Units (SI System) –Conversion of Units –Length –Time –Mass

4. Measurements  Use laws of physics to describe many different physical systems –Small set of simple laws –Common language is mathematics  Test laws by experiments –Select smallest set of standards and derive other standards –International Bureau of Weights and Measures (Paris), National Bureau of Standards, etc. –Système Internationale (SI), International System of Units, metric system, or mksA system

5. SI Units Length meter m Masskilogramkg Timeseconds Electric currentampereA Thermodynamic temperaturekelvinK Luminous intensitycandelacd Amount of substancemolemol Why should we care about SI units? Mars Climate Orbiter: http://mars.jpl.nasa.gov/msp98/orbiterhttp://mars.jpl.nasa.gov/msp98/orbiter

6. 10 x PrefixSymbol x=18 exaE 15 petaP 12 teraT 9 gigaGGeV 6 megaMMeV 3 kilokkeV 2 hectoh 1 decada Prefixes for SI Units

7. 10 x PrefixSymbol x =  1 decid  2 centiccm  3 millimmm  6 microµµm  9 nanonNm  12 picopPm  15 femtoffm  18 attoa Prefixes for SI Units

8. Example of Length MeasurementsLength (m) Distance to 1 st galaxies2x10 26 Distance to Nearest Star (Proxima Centauri) 4x10 16 Distance to Pluto6x10 12 Radius of Earth6x10 6 Height of Mt. Everest9x10 3 Thickness of this page1x10 -4 Radius of hydrogen atom5x10 -11 Radius of a proton1x10 -15

9. Time  1 second is the time taken by 9,192,631,770 oscillations of the light emitted by cesium-133 atom  Speed of light c=299,792,458 m/s

10. Example of time MeasurementsTime (second) Age of Universe5x10 17 Length of a year3x10 7 Length of a day9x10 4 Lifetime of muon2x10 -6

11. Mass  Standard 1: a platinum-iridium cylinder in Paris  Standard 2: Carbon-12 has 12 atomic mass units (u). 1u=1.6605402x10 -27 kg

12. Example of mass ObjectsMass (kg) Sun2x10 30 Moon7x10 22 Ocean Liner7x10 7 Human Body6x10 Speck of dust7x10 -10 Proton2x10 -27 Electron9x10 -31

13. Units  Language is mathematics  Equations  Diagrams/visualization  Quantities have dimensions  Results have units  Consistency

14. Precision  Measurements –Uncertainties Absolute Percent –Calculation Result can not be better than data Use scientific notation to show significant figures –Examples 3.14 + 0.5 = 3.6 123,400,000 = 1.234 x 10 8 0.003 = 3 x 10 -3

15. What is the radius r of the Earth? (h = 1.70 m and t = 11.1 s )