Physics quiz corrections and the first Winter IDEAl solution are both due next Wednesday, Jan. 31.

For quiz corrections, please use the fresh, slightly revised copy of the quiz posted here.

The problem for the IDEAl solution is based on the 3rd quiz question but with one small addition. To get a sense of whether your answer to the new part is reasonable, you might compare with this video of a system based on the same principles at work on the International Space Station (fast forward to 1:45 if you want to skip to seeing it in action).

For a refresher on what my rationale and expectations for the assignment are, please review the post from Fall quarter where I explain both.

Download (PDF, 102KB)

Download (DOCX, 19KB)

Here are my solutions to the Week 11 homework. Don’t forget – physics quiz in physics lab this Tuesday!

Download (PDF, 4.75MB)

Below are solutions to Week 9 homework problems, as well as answers to all the physics quizzes this quarter.

Download (PDF, 4.28MB)

Download (PDF, 7.62MB)

I (John) plan to spend much of the day in the lab classroom (2238 Lab 2). Feel free to drop by with any questions as you prepare for the final week of the quarter! I expect to be there from roughly 10 AM to 3 PM, with a lunch break in there somewhere around noon…

Update: I won’t be on campus until later, probably 12:30 or so.

Second Update: OK, I’ve arrived (12:40). I understand at least one person came by looking for me. I’ll try to stay later than I originally said; I also may have to make a quick run back home if the electrician needs me.

For revision, I nominate #3 (the falling spool). These are due at the final Physics review session (1 PM next Tuesday, room Sem 2 C4107).

Download (PDF, 164KB)

Posted below is Quiz 7. You may, as always, submit corrections to any questions on the quiz. In addition, the question for revision using the IDEA format is #2.

A very popular incorrect answer to #2 involved treating the problem as if it were in one dimension. It is crucial to remember that momentum is a vector quantity, and that your equations must treat the conservation of x and y components of momentum independently. You cannot write a single equation like m_A v_A + m_B v_B = (m_A + m_B) v_f and expect to obtain a correct answer. It should also concern you that nothing about such an analysis tells you in what direction the cars will be moving after the collision. If, by contrast, you have the x and y components of velocity, you have fully specified the velocity vector, and could obtain a speed and direction by applying right triangle trigonometry using the components.

Download (DOCX, 19KB)

As we approach the end of the quarter I’d like to share my plans for wrapping up the work in physics lab. We have just one more regular lab remaining in Week 9 when we come back from break, with part of the week 9 lab set aside for cleanup.

The Week 9 lab is essentially a series of activities without any prolonged data analysis, and my plan is to collect lab notebooks at the end of lab that Tuesday. Remember that your lab notebook is your primary record (and evidence of) your work in Physics lab, and will be an important element in demonstrating your learning in this component of the program. If you have significant work missing from your notebook, please try to remedy those omissions before the next lab session.

I plan to return your notebooks by the end of Week 10.

Below are my (messy, terse) solutions to the Week 7 homework

Download (PDF, 4.5MB)

This week I had the pleasure of writing two (very similar!) quizzes, provided below. I’d like to ask for revisions on #3 (you can do it for the quiz you took or the other quiz if you prefer), and of course you may also submit corrections to your original quiz.

Please try to complete and submit revisions by our next physics quiz on Wednesday next week.

Download (DOCX, 33KB)

Download (DOCX, 34KB)

I have compiled a document listing essentially all the equations I expect you might have put, or will put, on notecards for the quarter, based mainly on what is in chapter summaries in Wolfson. This is in the fileshare under physics handouts and included here as well.

I have formatted this as a set of tables organized by chapter with plenty of whitespace associated with each equation. My hope is that you can use this sheet as a study aid in two ways: first, by consulting it when making decisions about what to put on a notecard for a quiz, and second (and more importantly!), by taking the time to fill in the boxes next to each equation with notes about its meaning and/or conditions for validity. So for instance, you might annotate the equation v=v_0+at by reminding yourself that it is valid only when acceleration is constant.

I should also add that I tried not to impose my own standards on this list. When it comes to notecards, you should exercise some judgment. Don’t put equations that you already know well, and don’t just put everything from my sheet just because it’s on this list. Sometimes you might wish to use a different form. For instance, I’d be inclined to just write conservation of momentum as p_1i + p_2i = p_1f + p_2f rather than the textbook’s form m_1i v_1i +… because I also know p=mv. Also recognize that older chapters are still relevant; Chapter 2 kinematic equations will come back time and time again, and you might need them on every quiz. You should also make some calls regarding how much annotation you need to put on your cards.

Please let me know if you find any typos on these equations!

Download (PDF, 110KB)