March 30 
March 31 
April 1 
April 2 
April 3 





very short reading quiz due by 1 pm today..... now available on moodle if you are missing today's class for a prearranged absence, the quiz must be submitted by 8 pm Sunday quiz next tuesday or wednesday ?? (we're waiting on votes from david and haoyang) on chapters 1 and 2 

what
we'll do in class 
more
relativistic dynamics 
finish
chapter 2 
last
chance to practice Lorentz transformations and mass/energy stuff: problem 1(23) the fasterthanlight jets observed in quasars.... at what speed (v/c) will the mistake we make by using the nonrelativistic formula for KE be larger than 1%? 
start
nuclear physics 

(always done before class) 
1st pages of chapter 2, pp. 4143 fill in the 3 rows & columns we had on the board friday:

+ examples on page 44 + examples on page 49, especially example 6 


13(2 up through/including example 3) then submit reading quiz above in moodle 

inclass
presentation 

homework (by 5 pm) 
1(23) and 1(26) as a matrix equation of the form a xbar ( ) = b ctbar ax [L(v/c) ] ( ) b ct where ax ( ) b ct represents a vector matrix of event coordinates in one frame and L(v/c) is a 2x2matrix that represents the operation that transforms the event coordinates (x, ct) in frame S to event coordinates (xbar, ctbar) in frame Sbar 
problem 1(20) also, < 
so you remember the formula for electic energy? do you remember how to start a conservation of energy problem? ask if you're not sure 

(wherein you are encouraged to do as many LTs as possible; however, each part can also be done as a length contraction, OR time dilation OR timelapse problem (a la Tonya & Reid) 





you can start the prelab this weekend! 




do some problems out of chapter 2
on mass, kinetic energy, and total energy for practice 


March 23 
March 24 
March 25 
March 26 
March 27 



(rotated reference frames) to class (those who didnt have it quite right last Friday, please fix it for class today).... each coordinate in the rotated frame (xbarp, ybarp) should be a linear combination of the coordinates (x_{p}, y_{p}) in the original frame [combine your terms; there should be no denominators, and no trig fucntions multiplying other trig functions] 
bring to class TODAY: given a 2x2 matrix M with the elements a b c d find the elements of the inverse matrix M^{1}, such that M M^{1} = M^{1} M = the identity matrix: 1 0 0 1 
write the LT equations 1(23) and 1(26) as a matrix equation of the form a xbar ( ) = b ctbar ax [L(vc) ] ( ) b ct where ax ( ) b ct represents a vector matrix of event coordinates in one frame and L(v/c) is a 2x2matrix that represents the operation that transforms the event coordinates (x, ct) in frame S to event coordinates (xbar, ctbar) in frame Sbar 

what we'll do in class 
make progress toward understanding why the distance from the origin of any point is the same in both reference frames 
more
about the rotation matrix R(q).... if we define v to be the matrix vector containing the coordinates, then vbar = R(q) v represents the matrix transformation of coordinates that we wrote down in class yesterday show how the Lorentz transformations include both time dilation and length contraction principles that we have learned 
learn how to do velocity tranformation problems properly finally learn what it is that makes the distance between any two points in the xy plane absolute (and independent of choice of coordinate system) [and of course what makes the "interval": the same in all inertial reference frames 

(always done before class) 
section 1(7), an alternative derivation of the invariance of "the interval" section 1(3): how the MichelsonMorley experiment proved that the speed of light is the same for all observers 

this is a change from what I said in class on Tuesday 
< 
what are the new correct formulas for kinetic energy, total energy of particles "with mass" and particle without "rest mass" ? 
inclass
presentation 
do
you have one for this week? you don't have to make up your own! there are plenty in the back of chapter 1 !! 

homework (by 5 pm) 


find v/c by two different methods: 1) a time dilation problem 2) a doppler shift problem (make sure that you let me know who has the flasher in your doppler problem) 
prelab for lab E2 due at beginning of class (lab) web site for finding daughters, halflifes, etc (type the nucleus you're interested in inside the box at upper left corner; for example if you want info about carbon12, type C12) 
please do 28b as a length contraction problem 




we do lab E2 IF the alpha sources from last year are still viable 



have a presentation problem ready for today or this week? what IS the cause of the redshifts of galaxies? unfortunately, Serway's Chapter 16 on Cosmology (on line only) is equally bad at explaining the true reason for galaxies' redshifts [see for example equation 16.1 # equations 16.6  16.8  although at least these contradict his incorrect equation 1.15 !!!!] he actually has the correct reason in equations 16.11 & 16.22 but he doesn't draw attention to them at all & they are spaced far apart in the text otherwise, chapter 16 is pretty well written and a nice summary of the evidence for the Big Bang & dark energy 


March 16 
March 17 
March 18 
March 19 
march 20 




(i.e. read your manual!!!) you'll also need a lab book for lab today.... it does NOT have to be a new one; one you used in a previous course will do 


what
we'll do in class 
start
the muon problem 
finish
the muon problem & come up with a procedure for length contraction
problems 
lab E1 (link below, but I will provide copies) 
Doppler effect doppler effect applet 

(always done before class) 
pp. 1620 (also, I forgot to ask if you had questions about the invariance of perpendicularlength handout) 
given the muon problem that we started in class yesterday: consider the cloudground distance (defined by those 2 endpoints).... you know (from class) that we want to make that distance largest from the earth frame .... so what question can we ask (analagous to the one for time dilation: which observer says both events occurred at the same coordinates?) about the two endpoints such that the answer is the earth frame? bring a question that satisfies the above conditions to class today 
relook at the table we created for the muonearth problem.... and decide which things in the table are "exact" (in the sense that we defined them, so that they have an infinite number of 0's after the decimal) and which things are only "approximate" in the sense that we calculated them by approximating v/c as 1 if we actually recalculate these quantities, using v/c = 0.999949999 (instead of v/c = 1), does the quantity Dx^{2}  c^{2}Dt^{2} become the same in both frames? 
pp. 533534, on how a Geiger Counter works (the first couple pages of 13(4) and all of 13(6) might help you answer some of the lab questions if you are culturally illiterate 

inclass
presentation 

homework (by 5 pm) 
wrong problem 
the heartbeat problem make sure you turn this into a time dilation problem 
in case you need to come and get help the return of Tonya and Reid: now Tonya stands at the back of the train, where the light also is... consider the two events" 1) light leaves the back of the train 2) light returns to the back of the train Since you know the time between the two events according to Tonya, you can do a time dilation problem to find the time interval according to Reid; but Reid can also solve the problem by doing a dvat, even though he doesnt initially know the length of the train, according to him. By equating the two method's answers, show that the train length according to Reid is g (gamma) times smaller than the length of train according to Tonya use the applet at the following directory path: T:\Student\kolena\Relativity_Physlets\ contents\s_relativity\sp_rel\section2_4.html OR use this link in a browser on the NCSSM network in either case USE THE LIGHT BEAM CLOCKS at the BOTTOM of the applet 

.... and remember to solve for v/c, NOT v 




lab E1 





March 9 
March 10 
March 11 
March 12 
March 13 


and course expectations look at the textbook's Table of Contents 

bring a copy
of "The Complete Guide to Force Diagram Solutions" to class (and have read it!) 

make sure you have your calculator
for class today (I don't want to send you back, and have to mark you late) 
what we'll do in class 
we will talk more about violations of N's 1st law.... so in class yesterday, you all went from (mostly) denying that you had ever seen an example of N's1stlaw violation to... examples are everywhere..... so let me tighten the requirements a little bit... it's fairly easy to find examples in which YOU (as judged in your own frame) have 0 acceleration, yet have a net force acting on you..... now how about some examples of the opposite situation: objects which are accelerating, yet have zero apparent net force on them! 
centrifugal forces and coriolis forces: what are the equations describing the forces and how do they work? the movie clip with the ball thrown on the merrygoround... make sure that the ball does indeed go straight (after release) in the earth frame by stepping through the clip frame by frame 
begin classifying physics quantities (simultaneity, position, velocity, time intervals, etc.) as to whether they are relative or absolute to different observers your book does one of these in the section 1(5) reading for today 
learn the procedure for time dilation problems (we do problem 10, chpater 1) 

(always done before class) 

the TAN handout on "Rotating Frames of Reference; Inertial Forces" 

the BUFF handout on the absoluteness of perpendicular lengths ALL of yesterday;s reading, if you did not do it (we only read section 1(5) in class 

inclass
presentation 

homework (usually by 5 pm, but sometimes for class) 

Rel_of_Simultaneity.htm at T:\Student\kolena\Relativity_Physlets\ contents\s_relativity\sp_rel\section2_3.html to help answer the Tonya/Reid question bring your answers to class 
the improved version of yesterday's homework 

sideways displacement of a baseball thrown south from the pitcher's mound to home plate, at a reasonable speed, in Durham (or the displacement of any sports ball, kicked, thrown, or hit) document the numbers you assume to start the problem use the Coriolis effect formula that we learned in class! 









