When looking at a moving vehicle's rim . Why does it appear to be moving backwards sometimes.?

Answer 1

Well, your eye can see a specific number of pictures in each second. you can think of it as very fast changing pictures in front of your eyes.
so In case there is a moving wheel, it starts to be OK, then when it reaches the speed of human eye pics #/sec, it looks standstill, then when it's faster you eye takes one picture then by the next picture the wheel would have moved more than one cycle (i.e. less than full two cycles)so it looks like being moved in the opposite direction.
You can see that in case of computer screen and TV. They are flashing pictures, but we don't see that fact because the pictures are faster than our eyes, But when you record TV or Computer screen (by a vedio camera), you find that the pictures are on and off due to the recording that slowed it down a little bit.
I hope that helped!

Answer 2

It's kinda like animation. You know how a cartoon is made up of a bunch still pictures shown one after the other in a rapid pace.
The human eye sees at about 24 frames per second. So it gives the illusion of movement.
Well it the same thing with the tire going round and round. But it's going around very quickly. Say the rim was in the form of "X"
The four ends of the "X" are at 10:00, 2:00, 4:00, and 8:00.
a micro second later, they may be at 11:00, 3:00, 5:00 and 9:00 etc. etc.
But since the human eye only sees 24 frames per second and the wheel is spinning so fast. The next frame they may perceive may be at 9:00, 1:00, 3:00, and 7:00... giving the illusion the wheel is actually spinning backwards.
Trippy Huh?
wayne

Answer 3

It is due to Stroboscopic effect. You can find detailed explanation below:

http://en.wikipedia.org/wiki/Stroboscope

Answer 4

Because it's not put on centrally.