In article
,
harry k wrote:

On Jul 15, 9:42*pm, Smitty Two wrote:
In article
,
*harry k wrote:



Think about it for a minute: *All the parts are rotating together.
Right?
All the parts of a wheel rotate together. *Right? *So just what is
prepsterous about it?

Let's say there's 4 repeating features on the screwdriver bit (the
square sides), 3 chuck fingers, and 10 grooves around the outer diameter
of the chuck. The strobe couldn't make them all appear to turn backwards
at the same RPM. Oh, yeah, there's also the threads on the drywall type
screw that are turning backwards.

Well of course they all rotate at the same speed, they are fixed to
one another. In real life they are also rotating at the same speed so
why wouldn't they in strobe effect? The fact that some of them are
farther out from the axis does not effect their position when the
strobe hits. Somehow you seem to think that everything is rotating at
different rates

You could build a wheel 6' in diameter and tie rags aroudn the spokes
at diffent distances from the axle and they would all show the same
effect.
.
Harry K

It's an RPM (revolutions per minute) vs. RPM (repetitions per minute)
thing.

Yes all the parts rotate at the same actual RPM. But it is the
repetition of a regular feature (spokes) that causes the wagon wheel
illusion. If the drill is really turning at 100 RPM, then in my example
above, the frequency of the features going by your eye will be 400, 300,
and 1000 repetitions per minute. So as far as the wagon wheel effect is
concerned, the various parts of the drill are turning at different RPMs,
i.e. they couldn't all exhibit the effect at the same actual RPM.