B Why doesn't the Earth at the equator experience a sonic boom?

[ardnog]

Do you have a source for that? Surely nobody noticed breathing problems while riding a horse and people experienced faster winds (and horse + wind). Sounds like an old wive's tale to me.

I heard it in the early 1980s on a British childrens's TV education show called Eureka in which actors dressed up in period costumes and re-enacted the creation of famous inventions. So based on western technological progress and British culture I assume it stems from the industrial revolution era.

I tried to find the quote with google, and the best I could do was a misattribution to Dionysius Lardner who was misattributed as saying "Rail travel at high speed is not possible because passengers, unable to breathe, would die of asphyxia". https://en.wikiquote.org/wiki/Dionysius_Lardner

I feel that going further will involve contacting the BBC or purchasing the old TV episodes, so I've now reached the limit of the amount effort I'm prepared to put into defend the quote. :-) While it does sound like a ludicrous statement if true (and it may not be true), it wouldn't have been the dumbest thing that's ever been said by an expert.

 

[Janus]

Do you have a source for that? Surely nobody noticed breathing problems while riding a horse and people experienced faster winds (and horse + wind). Sounds like an old wive's tale to me.

When the first steam trains were introduced there was concern by some in the general populace that you wouldn't be able to breathe moving that fast, or that the vibrations would knock you unconscious. Of course these fears were unfounded, and anyone who put some thought to it, ( such as considering that, as you pointed out, people had already experienced comparable relative air speeds with no ill effects) would have quickly realized this.

 

[Klystron]

To help resolve possible confusion identified in earlier posts between the physics of air and water, atmosphere and ocean; consider using the simpler collective term fluid.

In physics, a fluid is a substance that continually deforms (flows) under an applied shear stress, or external force. Fluids are a phase of matter and include liquids, gases and plasmas. They are substances with zero shear modulus, or, in simpler terms, substances which cannot resist any shear force applied to them.

Along with helping understand underlying concepts such as shear and friction, using the term fluid includes water vapor in the atmosphere, dissolved gases in the ocean and relevant transitions such as ice, fog, steam, clouds and rain; and measures such as temperature and density that influence 'speed of sound'.

 

[anuttarasammyak]

The examples of fluids move with solid surroundings are

Newton's bucket : water in the rotating bucket also rotate with same angular speed with the bucket

Centrifugal Uranium enrichment : UF6 gas in rotating cylinder also rotates with cylinder and get centrifugal force according to isotope weight.