Re: out-of-the-box thinking

[John Clement <clement@HAL-PC.ORG>]

Oops, I didn't look closely enough, and interpreted it as a strobe
diagram.  However, my comment applies to a strobe diagram where the
spacing increases left to right.  And students really do have the
problem I alluded to.

John M. Clement
Houston, TX

> -----Original Message-----
> From: Forum for Physics Educators [mailto:PHYS-L@lists.nau.edu] On
Behalf
> Of Herb Schulz
> Sent: Wednesday, June 04, 2003 7:27 PM
> To: PHYS-L@lists.nau.edu
> Subject: Re: out-of-the-box thinking
>
> On 6/4/03 7:04 PM, "John Clement" <clement@HAL-PC.ORG> wrote:
>
> > On the other hand the value of the acceleration is positive assuming
+
> > is to the right.  When you ask if the answer is different for the
value
> > of the acceleration if you assume a different direction of motion,
many
> > students will say yes!!!!!
> >
> > John M. Clement
> > Houston, TX
>
> Howdy,
>
> Psst... The machine always SPRAYS THE Paint for the same length of
time.
> Since each of the lines is the same length the machine must be moving
at a
> constant velocity DURING THE SPRAYING. It may either be speeding up
> (assuming it's moving left to right in the figure) and then slowing
down
> between the sprays (so that the speed when the paint sprays is the
same)
> and
> the acceleration and deceleration must be getting larger in magnitude
- or
> -
> the time BETWEEN sprays could be getting larger - or - some
combination of
> these two things.
>
> Good Luck,
>
> Herb Schulz
> (herbs@wideopenwest.com)