University of Delaware

PHYS146

Notes

Announcements

A problem with the link from my home page to the course page has been fixed. If you were having trouble going through my home page, please try again.
I don't know of any editions of A Brief History of Time that are significantly different from the one in the bookstore. The page numbers given in the notes may or may not agree with the page numbers in any given edition, but the sections and chapters should agree.

Assignment: Write one paragraph proving that the table of atomic nuclei can be constructed assuming that nuclei are made up of protons and neutrons. Email your write-up to mvb@udel.edu by Tuesday, Feb 23. I anticipate that the paragraph will be fairly easy to write and will therefore be manageable even for those who need to learn the EMail system in order to get it submitted.

Assignment: I will take the assignment through midnight tonight. After that, submissions will get partial [half] credit only, unless you include a statement of a legitimate reason for not submitting the assignment earlier.
I have placed a set of study questions for the first exam on the web. Check Exam Information, Exam 1 notes.
Thursday I will solicit opinions on the best time to have a question and answer session on the first exam.

The first exam is scheduled for next Thursday, 3/4, in class.
There will be a question-and-answer session for the first exam next Tuesday, 3/2, at 7PM, in Sharp Lab 100. I have had to choose Tuesday over Wednesday to minimize the chances of my having an urgent family conflict with the time of the session.
Assignment: [Idea from H. Shipman] A pole vaulter is carrying his pole in a horizontal position over his head. The pole is 50% longer than an open shed which he can run through, with pole and shed compared when they are at rest with respect to each other. The vaulter runs so fast that an observer on the shed measures the pole to be slightly shorter than the shed. As the vaulter passes through the shed, there is a brief and sudden shower that starts after the pole is completely inside and ends before the pole first comes out the other side. The observer on the shed of course concludes that the pole does not get wet. However, from the standpoint of the vaulter, the shed is quite a bit shorter that the pole. Does the vaulter conclude that the pole gets wet? If not, why not?
Send your answers by EMail to Robert Huber (rth@udel.edu) before class on Tuesday (so that we can discuss the answer before the exam). As in the last assignment, the answer requires no new ideas, just direct application of an idea in the notes.

The exams will be returned Thursday.
Assignment 3: Find the fifth and sixth leptons and their antiparticles in the data table. Explain why they are leptons/antileptons. Are there any more leptons in the table? How do you know?
Send your answers by EMail to Robert Huber (rth@udel.edu) before class next Tuesday.