How can we characterize air resistance?

posted Mar 11, 2018, 8:31 AM by Barbara Fortunato   [ updated Mar 22, 2018, 7:45 AM by Barbara Fortunato ]
2: T 3/20 lab, 4: SNOW DAY W 3/21 lab Th 3/22 & F 3/23

Today, we will study "velocity dependent forces."  We'll get back into the swing of mechanics by doing a lab where we investigate the concepts of air resistance (drag) and terminal velocity.  You'll take advantage of available technology by using motion sensors or by analyzing videos you take and graphing position vs. time and velocity vs. time in LoggerPro.  In the end, you'll see how drag force relates to velocity.  

Homework:  Lab in journal due Friday, March 23rd.  LAB QUIZ on Friday!  Make sure to answer the following questions in your lab write-up in addition to the usual stuff:
  • Describe air resistance.
  • What equation relates air resistance to force of gravity on the falling object? (think sigma F)
  • What are some real life situations in which a person observes air resistance?
  • What are some situations in which air resistance is a problem?
  • What are some variables that affect air resistance other than velocity?
  • Why does this procedure work as a controlled experiment? (What else are you holding constant)?  
Watch the following video on velocity dependent forces. At time 6:00, pause the video and practice solving the differential equation on your own. (It will probably be faster than watching the whole video.) After you make your best attempt, fast forward to see if you were right. Then, at 17:00, listen to the notes at the end. Be prepared for a daily quiz next class.

Retarding & Drag Forces (Dan Fullerton)