FredB wrote:The problem with the number 10, is that calculations always use powers of 10---that is, your answer may be ten to the power 6, 7, ---etc. Get this number wrong and you have an aborted space mission---it has happened.
You see the thing about the number 10 is that that is the base of our numbering system, so of course when talking about very large, or very small numbers, we are going to have to use an exponent notation and express numbers in powers of 10. If we used a different base, e.g. 60, as used by the ancient Babylonians, we'd express numbers in powers of 60. Good luck with that.
It has absolutely nothing to do with the Imperial vs Metric "debate". If you disagree, please show why we would intrinsically write the average distance from the Sun to Mars as 143,000,000 miles and not 1.43E8.
There are 1760 yards in a mile. This number is not habitually used for anything else and hence is easy to remember correctly.
And there you have it. You have to
know and
remember that. If you misremember, any calculations you do where you convert yards to miles will be wrong.
OTOH, it's not possible to get the number of metres in a kilometer wrong unless you simply don't know the ISU prefixes.
Can you explain why having to remember how many yards there are in a mile, or how many ounces in a pound, is less likely to go wrong than knowing that kilo means 1000, so km, kg, kA, kV etc are 1000 metres, 1000 grams, 1000 amps, 1000 volts, etc?
There are other more practical metric problems: the metric screw thread system is a bad one, Standard ISO metric threads are too coarse and a sloppy fit.
Hmmm...
(Obviously -7BA and -8BA don't exist, but if they did, those are the pitches they would have.)
The imperial system evolved over a number of years through practical experience. The metric system was decided by drones in committee meetings, mostly with no experiece of the devices and systems that they were standardizing.
Do you have any evidence to support that assertion?
Do you think that standardisation of screw threads is a good thing, or a bad thing? Would life be easier or harder if every engineering/manufacturing company in the world had their own screw threads, incompatible with everybody else's?
If we are to have standards, should they be developed and maintained, "owned" if you like, by private corporations or by standards bodies? Would life be easier or harder if every engineering/manufacturing company in the world had to make different versions of their products if they wanted to export them to other countries? Or if it were done the other way round would life be easier or harder if garages, say, had to stock dozens of different systems of screws, nuts, bolts, washers, spanners and so on in order to be able to maintain cars?
https://en.wikipedia.org/wiki/Screw_thr ... ardization
I used to design trucks. Many parts and systems in automotive engineering last longer than the market life of a vehicle in production. In the late 1970's, we had metric cabs sitting on imperial chassis fitted with metric engines coupled to imperial gearboxes. All brought about by the desire for standardization!
Can you explain how it would be better if the threads on Iveco trucks were different from those on Ford, and both were different from Volvo, and all 3 were different from DAF, and all 4 were different from...?
In short, can you show why standardisation, per se, is a Bad Thing?
The USA got it right by refusing to change from an old, well proven system to a new, unproved and less user friendly replacement.
SAE? That was neither Imperial nor ISO.
A ½" United States Standard thread screw would have had a TPI of about 12.5, so somewhere between ½" BSW & ½" UNC.
UNC and UNF are of course US standards, and the former is coarser than BSF but finer than BSW, and the latter pretty much the same as one of the fine ISO Metric sizes.
Which ones are more, or less, user friendly than others? And why?
Unproven? ISO Metric is what, 60-70 years old? How long before it is proven?
