Re: A Riddle for Relativists.


"Dr. Henri Wilson" <HW@....> wrote in message
news:8i17249687mra3f21atbjn9nh1g20jseub@xxxxxxxxxx
| On Thu, 8 May 2008 14:16:49 +0100, "Androcles"
<Headmaster@xxxxxxxxxxxxxxxx>
| wrote:
|
| >
| >"Dr. Henri Wilson" <HW@....> wrote in message
|
| >
| >
| >The turns of your car's wheels are ACTUALLY COUNTED.
| >They are not the miles the car has travelled or the engine's revolutions,
| >so throw away the rev counter (which measures rate anyway)
| >and the odometer.
| >(In reality the take-off is from the drive shaft and before the crown
wheel
| >and pinion - it only works by having an exact ratio - and that's what
| >you have in the clock, an exact ratio)
| >
| >Your point is moot.
|
| My point is that one doesn't count the wheel turns by measuring the amount
of
| fuel used.

25 mpg, 12" radius wheels, 5280 feet to the mile,
840 wheel turns per mile, 25 * 5280/2pi = 21,008 wheel turns per gallon.
Why not?

A strobe is often used to measure engine RPM.
When the shaft appears stationary in the strobe light,
the frequency of the strobe is used to measure the engine
RPM. What's wrong with that?
Only one thing. The RPM can be any exact multiple of the
strobe frequency and still appear stationary.
For low ratios we can be fairly certain that an engine designed
to run at 1000 RPM and a 1000 Hz strobe isn't running at
2000, 4000, 8000 or 16,000 RPM, but if its only a 100 Hz
strobe we are less certain about it being 1,000 or 900 RPM.


.

Relevant Pages

  • Re: A Riddle for Relativists.
    ... |>|>The turns of your car's wheels are ACTUALLY COUNTED. ... |>A strobe is often used to measure engine RPM. ... Since both the wavelength (as measured by a change in angle ...
    (sci.physics.relativity)
  • Re: The Emission Theory of Androcles
    ... has to increase the wavelength. ... You don't change the frequency of the strobe. ... 45 RPM to> 78 RPM. ... taking off smiley faces and ...
    (sci.physics.relativity)
  • Re: The Emission Theory of Androcles
    ... has to increase the wavelength. ... wrong>>or the> distance between marks isn't the wavelength. ... You don't change the frequency of the strobe. ... 45 RPM to> 78 RPM. ...
    (sci.physics.relativity)
  • Re: The Emission Theory of Androcles
    ... or the> distance between marks isn't the wavelength. ... You don't change the frequency of the strobe. ... You can only change the speed from 33 RPM to 45 RPM to ... at 33 rpm the illuminated spots on the card stand still at 33 RPM ...
    (sci.physics.relativity)
  • Re: GAS ELECTRIC ENGINE
    ... car gas electric train, moving from a dead stop, requires the engine, running at hundreds of RPM to be coupled to the wheels, running at zero RPM. ... The only workable transmission in that era was electric, an engine powered generator and street car style traction motors turning the wheels. ...
    (rec.models.railroad)