Scantron scores are UP.

Your scantron scores are UP in Webcourses2.

Each item was 2 points, so your score reflects the number you got correct ×2.

Yesterday's podcast is UP, but...

Yesterday's lecture podcast is UP, on our iTunes U area, but the audio seems to cut out midway. All the slides are there, though, as usual, in the artwork track, including the scans of the document cam pages.

So everything you saw is there, but not quite everything you heard.

Written homework 5 is ready.

Go download your PDF of written homework #5. It includes some "push" goals if you really want to prepare diligently for the midterm examination.

Office hours tomorrow are 11 AM - noon, PS158 in the Physical Sciences Building.

Written homework 4 is graded and ready.

In Webcourses2, I have posted everyone's grade for written homework #4. I will hand them back in lecture today.

WebAssign homework is ready.

Your WebAssign homework for Monday is ready.

In addition, the diagram above and the following queries* are something to consider as you study:

1. Two blocks, of masses M = 3 kg and m = 2 kg, are in contact on a horizontal table.
2. A constant horizontal force of magnitude F = 5 N is applied to block M as shown.
3. There is a constant frictional force of magnitude f = 1 N between the table and the block m, but
4. no frictional force between the table and the first block M.

That being the case, can you calculate the acceleration of the two blocks? Can you calculate the force of contact between the blocks?

Inquiring minds want to know!

---

* Adapted from French, A.P., Newtonian Mechanics, New York: W.W. Norton, 1971.

Class cancelled today, Wednesday

Due to evacuation of the MAP building, we will cancel lecture today, Wednesday.

I will see you on Friday, so bring that written homework and I will collect it on Friday.

Written homework 4 is ready.

Your written homework assignment for Wednesday is now UP in Webcourses2.

Updating iClicker 2 data

I have been updating iClicker 2 data this afternoon. Still some data sets to upload, but it is getting caught up.

If your clicker is #8514BC2D or #8DA2A28D...

If your clicker is #8514BC2D or #8DA2A28D, you are not earning any points for your semester grade. I can see you are clicking but I have no idea who you are. It is long past the time when your iClicker 2 registration was to be squared away.

Written Homework 4 will be ready Monday, due Wednesday.

Looking ahead, you'll get a new written homework assignment on Monday, probably related to work and energy.

That puts us back in the standard homework cycle. It will be due on Wednesday, returned on Friday.

WebAssign homework is ready now.

To see where we are heading in the next few weeks, this page, Kinetic energy etc., at Wolfram's ScienceWorld can give you a good idea.

Your WebAssign homework due on February 18 is now ready. This is a big assignment because energy is a big topic and very useful, so mastery is a good goal.

Image: Deep Impact probe collides with comet Tempel 1. [NASA]

Written homework 3 is UP.

You can now drop down the PDF of written homework #3 from Webcourses2. It is due on Friday at the beginning of lecture.

Iceland

I have posted your grades for the Iceland homework. Tomorrow I will hand it back. Until then you can view my solution in PDF on the "Written homework assignments" page.

Variations in the gravity of our moon

An interesting look at variations in the gravitational field of our moon, from the GRAIL spacecraft. Cf., Zuber et al., Science 8 February 2013: Vol. 339 no. 6120 pp. 668-671. DOI: 10.1126/science.1231507

Mercator projections of free-air gravity, topography, and Bouguer gravity. Frames in (A) highlight the area surrounding the Korolev impact basin, at center. Frames in (B) show the western limb of Oceanus Procellarum. Details of free-air and Bouguer gravity are the same as in Fig. 1. Topography is from a LOLA 1/64° grid.

1000 mGal = 1000 milliGalileos = 1 cm/sec². So the variations are small but telling.

Enjoy.

New WebAssign is ready.

Your WebAssign homework is ready now. It includes on problem from Ch. 5, so do a bit of reading ahead into Ch. 5 for Monday.