Alas, a rule, or even two rules, without reasons is not a clarification. What can be used under one condition or another does not tell us why it is used then and not now and how that choice is justified. Constant velocity, average velocity, instantaneous velocity and mean velocity are well-defined distinct concepts that can be used to explain the whats, the hows, and most importantly the whys. Let's talk about the concepts that lead to the rules. It worries me that many of these Advanced Placement Calculus discussions - Average Velocity is just the latest example - spend much more time on rules than on reasons.
In a message dated 10/31/2009 10:38:00 A.M. Eastern Daylight Time, SGold2112@aol.com writes:
I asked a physics teacher to clarify this issue about average velocity, and he said that average velocity is the same as the average of the velocities only if acceleration is constant, but he said even in that situation he still prefers to use the change in distance divided by change in time formula.
Also, in response to the question about the release of exams, the 2008 AB and BC exams will be available for purchase in December, according to an email I received from college board.
Steve Goldman Half Hollow Hills HS East Dix Hills, NY