Saturday, January 19, 2008

HW II is out / HW 1 and Quiz 1 results

I know you've been waiting anxiously ...

Same deal as last week - due some time before Friday, 25 Jan 2008 at 5pm. Massive hints will be given throughout the week in class.

By the way: the average for quiz 1 was 84.2%, and the average on homework 1 was 93.3%. Very well done. Below you can see the average score broken down by question for both the quiz and homework. What this tells me so far is that 1) velocity addition is hard, and 2) conceptual questions about relativity are hard.


Friday, January 18, 2008

Homework 1 solutions are out

Here you go.

Next week, we will start with electric forces and fields. Please read through the material before Tuesday - Serway Ch. 15 or Ch. 3 of the notes. We will cover roughly half of the material Tuesday, and the other half Thursday.

Thursday, January 17, 2008

Good relativity question & answer

Have a look at this, if you are curious. Well-thought answers to some tricky points in relativity.

Special Relativity Applets

Today in the second half of class we will go through some applets meant to familiarize you with the concepts of special relativity in a more intuitive way. You can find them here, I suggest opening them in a new window so you can still view this post.

There are 5 applets you can click through and play with a bit. You may want to play each animation a few times to carefully see what is going on. The applets cover:

1. Light clock and time dilation
2. Length contraction
3. Simultaneity of events
4. Space-time diagrams
5. Momentum in different reference frames

Once you have gone through all the applets, as a group, type up a short summary of what you observed in each of the first four applets, and write down the equation(s) most relevant to each one. You should play the fifth applet, but need not write about it. Try to answer at least the following questions for the first four applets, based on physical reasoning.

1. Why must the time interval be different for a moving and stationary observer?
2. Why must measured lengths appear shorter to moving observers?
3. What must be true for observers to always measure two events as simultaneous?
4. How does the space-time interval relate to the graphs, and why is it invariant?

Turn in one write-up per group, with all group member's names. Your report may be typed or handwritten.

Monday, January 14, 2008

Exercises for 15 Jan 08

Tuesday (15Jan) in class we will work on some exercises in groups.

Form a group of 3-4, and print one copy per group when you get to class.

UPDATE:

Solutions are now up as well. You can find both exercises and solutions here.