Class 090824

Request your access code today. 

Go to the form at

http://vhcc2.vhcc.edu/dsmith/_vti_bin/shtml.dll/request_access_code.htm

and submit, using your .  Then check your VCCS email. You'll get your code sometime this evening.

The syllabus for this course is at

http://vhmthphy.vhcc.edu/  > Physics I > Info

If you registered today, email the instructor for information.  If you registered before today, you'll have an email with this information.

The Submit Work Form is for communications with the instructor. 

• When you use the form, you will be asked to give you       r submission a title.  You can choose any title, but the title you give your submission should start with the letters 'ic', for 'in-class'.  For example, a title might be 'ic_first_homework_assignment', or 'ic_question_about_ramp_lab'.

In-class activities:

Make a pendulum and count the cycles that occur in a minute at two lengths, one short, one medium and one long.  Record the length (e.g, by tracing the short pendulum on your paper, by measuring the medium pendulum against your textbook, etc.).

Time things with the pendulum:

• Time a marble down a one-nickel incline using the short pendulum. 
• Time a marble down a one-nickel incline using the long pendulum. 
• Time a marble down a nickel-dime incline using the short pendulum.
• Time a marble down a nickel-dime incline using the long pendulum.

Can you distinguish between a one-nickel incline and a nickel-dime incline using the short pendulum? 

Can you distinguish between a one-nickel incline and a nickel-dime incline using the long pendulum? 

What is the percent difference between 5.5 and 8?

What is the smallest possible percent difference you think you could detect, using the pendulum, in the times required for the ball to travel down two ramps?

(deferred exercises--will be done next class) Drop a coin simultaneous with the release of a quarter-cycle long pendulum.  Find the minimum height at which the pendulum clearly strikes the wall first, and the maximum height at which the coin clearly strikes the floor first.

Walk down the sidewalk at constant velocity while someone times you with a pendulum of appropriate length.  Can they verify that you walked at constant velocity?

Walk down the sidewalk, increasing your velocity gradually while someone times you with a pendulum of appropriate length.  According to their results, did you speed up at a constant, an increasing or a decreasing rate?  According to your perceptions, did you speed up at a constant, an increasing or a decreasing rate?

What's the effect of one thin dime?

• Roll a marble down a one-nickel incline and let it fall to the floor.  Repeat until you can consistently hit the bottlecap.
• Without changing the position of the bottlecap, go to a nickel-dime incline and repeat.
• How much do you have to change the position of the bottlecap to succeed?
• Does this exercise distinguish the effect of one thin dime?

(deferred until next time)  Describe the motion of the dice on the ends of the strap, as you see them from your perspective.

Homework:

Dedicate a notebook to lab.

(deferred until next time) Take a pendulum home and give it an accurate count.  Submit using form at Pendulum Counts Report

Report your results from today's class using the Submit Work Form.  Answer the questions posed above.

Read Chapter 1 of your text.

View Key Systems by next Monday.  If you have time you can view them now.

http://vhcc2.vhcc.edu/ph1fall9/frames_pages/introduction_to_key_systems.htm

Do the preliminary question-answer exercise:

• Go to the Submit Work Form.  Fill out the identifying information (access code, email address, etc.), just type a simple 'hello' message in the last box, and submit.  The instructor will respond by posting a copy to your access site, along with a short comment.  Posting will typically occur on the evening of the day you submit the form, or on the following evening.
• Go to the document Preliminary Question-Answer and do as instructed. 
• Then go to the document Introductory qa and do as instructed.