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bc dimmer than usual, he hopes.
p.s. the sun and moon subtend ~ 1/2 deg. [~ 8.7 miliradian] So the
ball has a 23 cm D?
On 2009, Feb 18, , at 21:13, John Clement wrote:
You will see the same fraction of the basketball as the moon if the_______________________________________________
ball is
about 26m away from the observer, assuming I did the calculation
right. The
absolute distance is not the important parameter, rather the
subtended angle
or the ratio of size/distance are the important variables. The almost
parallel comment would also apply to a basketball at 26m. But the
rays are
not parallel. A grape at 2 m beats the moon for the fraction of
area you
can see with one eye.
While the reverse perspective comment is valid, it is probably not
a good
way to visualize how a magnifying glass makes more area visible.
And notice the problem changes if you use 2 eyes rather than 1.
For small
objects the visible area increases as you bring it closer if you
use 2 eyes.
The answer is correct, but with wrong reasoning.
John M. Clement
Houston, TX
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
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