Visual Effect - Wheels rotating backward at speed... | Page 2 | FerrariChat

Visual Effect - Wheels rotating backward at speed...

Discussion in 'Ferrari Discussion (not model specific)' started by Robb, Jun 19, 2008.

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  1. wax

    wax Five Time F1 World Champ
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    Jul 20, 2003
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    Dirty Harry
    I used to watch Dick Van Dyke show just to see the wheels spin bassackwards at the Intro...
     
  2. Maas

    Maas Rookie

    Jan 22, 2005
    40
    your eyes do not have a 'sampling rate' which you're referring to the frequency at which the frames are showing, ie 36 frames per second

    however all light, eminates at a certain frequency, it is the rotation of the wheel being in exact sync with that frequency which will cause a wheel to appear to be stationary and faster than this frequency to appear to be rotating backwards. This is why you can view this phenomenon in real life.
     
  3. fiorano94

    fiorano94 F1 Veteran

    May 26, 2006
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    Glad im not the only one. Happens when i space out.
     
  4. Brian Harper

    Brian Harper F1 Rookie
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    OK, so let's put 4,300 spoke wheels on your Veyron to get the spoke frequency way up there, shine red light on it to get the lowest frequency light on it, that would be around 430,000,000,000,000 Hz. To get close to the same frequency the wheel would have to spin at 100,000,000,000 rpm. Let's say you didn't opt for the super bling wheels, and the outside diameter of the wheel is 20". A 20" wheel has an outside circumfrence of 2*pi*r, for about 120". At 100,000,000,000 rpm the wheel would travel 12,000,000,000,000 inches per minute, divide by 12 for 1,000,000,000,000 feet per minute, divide by 5280 for miles per minute gives 189,393,939 miles per minute, times 60 for miles per hour is 11,363,636,363 miles per hour.

    Your gonna need some Z rated tires to try this at home.

    One of us is wrong. I'm neither a physicist or a mathematician. Could be me.
     
  5. Maas

    Maas Rookie

    Jan 22, 2005
    40
    I am wrong, apparently your eye does have a frequency at which it interprets light and it's 15hz
     
  6. Jack-the-lad

    Jack-the-lad Six Time F1 World Champ
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    Jun 22, 2004
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    Somewhat OT, but indulge me for a minute....In those old photos of race cars in motion, why do the wheels/tires appear to be oval instead of round?

    Jack.
     
  7. Choptop

    Choptop F1 Rookie

    Aug 15, 2004
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    persistence of vision.

    http://en.wikipedia.org/wiki/Persistence_of_vision
     
  8. bert308

    bert308 Formula 3
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    That is caused by the vertical movement of the shutter, the top of the picture is taken before the bottom and in the meanwhile the car has moved. That is what I remember.
     
  9. Brian Harper

    Brian Harper F1 Rookie
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    Where did you get that from? I've never heard of the eye having a sample rate.

    I found this:
    "A critical part of understanding these visual perception phenomena is that the eye is not a camera: there is no "frame rate" or "scan rate" in the eye: instead, the eye/brain system has a combination of motion detectors, detail detectors and pattern detectors, the outputs of all of which are combined to create the visual experience."

    here:
    http://en.wikipedia.org/wiki/Persistence_of_vision
     
  10. bert308

    bert308 Formula 3
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