SSG leaders

SSG leaders, I will be sending you a course mail message later today, in Webcourses.

No homework

No homework today. See you on Friday for regular lecture, and for more discussion of electrostatic forces.

CPS

Starting today, you are to consider a CPS device to be the equivalent of a scantron exam form. Therefore, operating someone else's CPS response pad is considered cheating.

I do not want to EVER see anyone operating two CPS response pads in lecture.

Hurricane Ida

500 mile radius circle:
its center is Huricane Ida, the red circle just east of Cancun;
it curves a bit beyond Miami and not quite as far as Orlando.

Here are some of this morning's specs on Hurricane Ida.  Note the central pressure, 983 millibars.

ESTIMATED MINIMUM CENTRAL PRESSURE 983 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 80 KT WITH GUSTS TO 100 KT.
64 KT....... 15NE 0SE 0SW 15NW.
50 KT....... 40NE 30SE 20SW 30NW.
34 KT.......120NE 70SE 40SW 90NW.
12 FT SEAS..150NE 120SE 75SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

A fair day at sea level has a pressure rating of 1013 millibars. Right now, Miami is reporting 30.06 inches, 1018 mb; Orlando is reporting 30.18 inches, 1022 mb. So right now: ΔP = -35 mb from Orlando to the eye of Hurricane Ida. That is only a 3.4% dip, yet it is an enormous change in the weather. Total distance from Orlando to the eye is approximately 580 miles. Excellent.

Hurricane Ida to Orlando

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1. National Hurricane Center
2. Orlando weather data
3. Computer models: where will it go?
4. Weather Channel update

Air pressure, the source of the F = ma that lifts a 747 carrying the space shuttle into flight. Amazing.

Friday's lecture podcast is UP -- as a video.

I made an experimental video version of Friday's lecture, based on Apple Keynote. It is regular audio on top of Keynote slides, mixed down into a Quicktime movie. For this reason, it is about 187 Mb in size... a hefty download.

Because it is so large, I slapped it into a new, special tab on our iTunes U page, as shown in the diagram: "Video lecture." It is significantly different from the enhanced audio podcasts from previous lectures. I am not sure yet if I like it, so see how you like it. Remember, we are the pioneers on iTunes U at UCF, so we have to sort out the good from the bad.

P.S. I still have a few regular enhanced audio podcasts to upload, from earlier in the week, Nov. 4 and Nov. 2!

Homework 21 has 10 questions.

Homework 21 is ready now. It has 9 regular type questions and one brain burner. HW 21 is due on Monday at the usual times.

GO TO IT!!!

Homework 20 will go active at noon today.

Your next homework, HW 20, will open for business at noon today. It will be due at the usual times on Friday.

HW 19 do-over

You can make another attempt on HW 19 to correct your score. It will stay open for business until 7 PM, Friday.

Homework 19 ready to go.

Your 19th homework assignment is now ready to go. It has a nice combo section that walks you through a full buoyancy force problem. It is due on Wednesday at the usual time.

Excellent meteor shower from direction of constellation Leo

Coming up in a few weeks is the Leonid meteor, best viewing between midnight and dawn, looking toward constellation Leo. Very cool. It is actually the leftovers of a comet that passes near Earth's orbit and leaves a trail of debris behind.

Excellent.