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Re: [Phys-l] A kinematics question

At 12:47 PM 6/28/2008, Josh Gates, you wrote:
"A runner runs around a 400-m track in 1 minute, 5 seconds. What was the
runner's average speed? The runner began the run from a standing start and
finished the run with a sprint at 20% more than the average speed. What
was the runner's average acceleration over the entire run?" ///
So... what do you think?
I will require:
- a snarky response about how this would be easier if we used bivectors
- a response with 2.3 x 10^8 references
- a post about how this problem was much better in the good old days with
a cryptic PS.




* unkind to the bivector approach: even *I* can tell that method
would have its advantages.

* unkind to providing references: even *I* could relate to the recent
proposition that a bare narrative stands alone, cold and defenceless
in the dark forest, but a predator needs to face down not only
one's narrative, but the support from all the references that the
narrative porports to suggest are in support of its position, if they
are given. [rightly or wrongly]

Now to the analysis - as keen and insightful as ever....
AVERAGE speed is distance over time, both of which are given.

AVERAGE acceleration begins with a stationary runner, and ends with a
stationary runner. The average horizontal acceleration would seem
then to be zero, if acceleration is taken to mean change of speed
with time. [a non-vectorial quantity??]

Brian Whatcott Altus OK Eureka!