Re: [Phys-l] Figuring Physics in the March TPT The Physics Teacher

["John Clement" <clement@hal-pc.org>]

Sharp eyes! As is so often the case diagrams can be easily drawn wrong.
Which is surprising in this case.  Indeed by fusing the two images one sees
that the diagrams do not show any difference.  This should not have happened
because Hewitt drew them himself.  The ray diagram does show why, but the
shading is certainly poor.  This is certainly not the big mistake, but it
can confuse students.  Perhaps he should have distorted the distance by
making the eye closer so there would be a greater disparity.

I think this is one where he really blew it!

John M. Clement
Houston, TX

> My first reaction is that the picture of the ball that is farther has
> roughly the same "visible" (lightened) area in the picture, so the first
> sentence is wrong. The diagram doesn't show any difference.
>
> BN
>
> > > > Bernard Cleyet <bernardcleyet@redshift.com> 2/18/2009 10:36 pm >>>
> OK, I give up; what's wrong w/ the basket ball and moon problem.
>
> bc evidently almost dead.
>
>
> On 2009, Feb 18, , at 13:50, John Clement wrote:
>
> > It has part of the analysis of the problem wrong.  Can anyone spot it!
> >
> > John M. Clement
> > Houston, TX