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Re: [Phys-L] [SPAM] Re: The Make-Believe World of Real World Physics




On 2013, Jul 30, , at 16:01, jbellina <inquirybellina@comcast.net> wrote:

No I don't think so, if it is digital is has to acquire for something more than an infinitesmal time. I'll have to think about the analog one.

joe


Hence the "s. The analogue is a rotating magnet inside a low resistance electrical cup (Al). So its response time is similar to a d'Arsonval meter.

bc's very long (time) delay line (many 0.6Fd caps and ~ 6mH inductors) requires d'Arsonval meters, and, as a kid dismantled a few speedometers.

p.s. from this description I suspect a digital speedometer can be designed to have a response in the microS "region".

HowStuffWorks "Eddy-Current Speedometer"

http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/speedometer3.htm

And is there such a "thing" as infinitesimal time?

A microwave company in Santa Barbara also made (ca 1960) a gasoline consumption meter using a ball race in series w/ the gas. line, a photogate and a mechanical register. Later they combined it with a speedometer connection to make an MPG meter. I installed the consumption meter in my VW and "mentally" approximated my actuel MPG.


On Jul 30, 2013, at 6:32 PM, Bernard Cleyet wrote:

Does not a speedometer give "instantaneous" speed.

Joseph J. Bellina, Jr. Ph.D.
Emeritus Professor of Physics
Co-Director
Northern Indiana Science, Mathematics, and Engineering Collaborative
574-276-8294
inquirybellina@comcast.net