Today’s PHSX213 class road-map

1. . Introductory general physics remarks You – introduce yourself Review course info. E-mail, diagnostic test Units, dimensions, vectors Definitive syllabus and course description will be published later in the week Today’s PHSX213 class road-map

2. PHSX213 What is Physics ?

3. What is Physics ? • The whole world – around us !

5. Why is an education in physics useful ? • You get to understand how nature works • And, from a perspective which yields insight and further understanding. • I am often accused by my family, of “thinking like a physicist” – sorry can’t help it !

6. Some examples of thinking like a physicist • Hurricane Charley • How to count • Sports Some deadly serious – others modestly amusing perhaps ….

7. Hurricane Charley

8. How to (Re)count My take on the 2000 Florida election debacle. The systematic uncertainties of the voting process were too large to distinguish candidates differing by of order 0.1%. i.e. too close to call !

9. Sports • Pick your favorite. • I grew up in Scotland and play golf (everybody does there) • Now after reading a book, by Dave Pelz, (NASA-trained physicist), I measure (pace off) EVERY putt !

10. Introduction • I’m now an assistant professor at KU ! • My research is in experimental particle physics. • Studying stuff like quarks, leptons, neutrinos, extra dimensions. • I worked for 15 years at CERN, Geneva, Switzerland. Measured invisible decays of the Z particle

11. So I’d like to know more about what you do – and maybe you can think a bit about how physics affects your world

12. Apparently random quiz • Where was the world-wide web invented ?

13. Think of a Physics Equation • So that we can discuss dimensional analysis. • See TACTIC 6 on HRW page 23

14. Spheres demo

15. Material I will assume you have learned / will learn (Ch. 1) • Standards • International System of Units (SI units/ metric) • meter (m), second (s), kilogram (kg) • many derived units eg. N = kg m s-2 • Scientific notation • Significant figures • Orders of Magnitude

16. Mars Orbiter • How much did this cost ? • 125 M$ • What happened to it ? • Burned up (too near Martian surface) • Why ? • NASA uses meters (SI) • Lockheed used feet • Careful unit conversion is important !

17. Unit conversion example • How many nanoseconds (ns) in 20 years ? • Gather the conversion factors : • 1 year = 365¼ days ; 1 day = 24 hours • 1 hour = 60 minutes ; 1 minute = 60 s • 1 ns = 10-9 s • 20 y = 20 y (365¼ days/y) (24 h/days) • (60 min/h) (60 s/min) (1 ns/10-9s) • = 20  365¼  24  60  60  109 ns • = 6.31  1017 ns

18. Vectors

19. The scalar product makes it easy to understand many physics concepts. Example : work W = F• d

20. The vector product makes it easier to understand many physics concepts. Examples: torque and angular momentum in rotation t = r F ; l = r p

21. Vectors • Vectors and Scalars • Adding Vectors Geometrically • Components of Vectors • Unit Vectors • Adding Vectors by Components • Multiplying Vectors • c = sa( multiplying by a scalar, s) • s = a•b(multiplying a vector by a vector to obtain a scalar) SCALAR PRODUCT • c=a x b(multiplying a vector by a vector to obtain a vector) VECTOR PRODUCT

22. Vectors and scalars • Scalars. • Single valued quantities • Mass, time, energy, temperature, pressure. • Vectors • Magnitude (size) and direction. • Can be 1-dimensional, 2-d, 3-d, n-d • Eg. In a lift shaft (1-d), pool table (2-d), mountain (3-d)

23. Adding Vectors → → → AC = AB + BC

24. Scalar Product The scalar product operation takes two vectors, a, b and forms a scalar. a• b = a b cos f

25. Vector Product The vector product operation takes two vectors, a, b and forms another vector, c whose magnitude is c= a b sin f, where f is the smaller of the two angles between a and b, • and the direction of c is at 90º to the plane formed by a and b, in the direction given by the right-hand rule. • We write c = a x b

26. Component forms • a•b = ax bx + ay by + az bz • a x b = (ay bz – by az) i • - (az bx – bz ax) j • + (ax by – bx ay) k