I used to teach AP physics to kids on the weekends. One asked me why Farads were so big. I had to explain that there’s a fixed ratio between Farads, Volts, and Joules. One of them had to be crazy big or crazy small.
See also Coulombs.
Caps are especially scary because they can develop their own charge through static electricity, so large value caps are often shipped with their terminals tied together.
There's nothing in the SI system that says ratios have to be between base units. Units that involve mass are defined against the kilogram not the gram.
You sent me down a freaking rabbit hole, thanks! :)
From what I found is that there is the simple reason that the weird ones are distance, time and weight - the rest I looked into are based on formal non-normalized definitions (including lumen, which surprised me).
My guess is that in depends on where the unit comes from: science or day to day use.
I learned about the Siemens, the Weber and the Gray on the way.
the international avoirdupois pound, [...] is legally* defined as exactly 0.45359237 kilograms
So, technically, a pound is a metric weight, only a niche one whose use may or may not be permitted by local regulations.
Similar is true* of the inch, which is defined as precisely 25.4 millimetres.
* The US, UK and a handful of others collectively signed this into their respective laws in 1959. You might think we don't use the pound in the UK any more but it still shows up often in informal situations. Ditto inches and feet.
That's similar to saying "Auf Wiedersehen" translated to English is "until I see you again", therefore "Auf Wiedersehen" is technically English. Just because there's a recognised translation to a thing, that doesn't make it that thing.
I would argue that a legally defined conversion to a meter or another metric value does not make a unit metric in and of itself. Those units have to adhere to the system, which is clearly based on decimal values, not just some arbitrary conversion with an absurd precision that was only signed into law to minimize the inconvenience caused by non-standard units.
No it's real! I can't verify the exact rating since it OL's my meter, but with some circuitry it can power my Pi for a few minutes.
I got them from element14, so it's unlikely to be a fake product.
But why pick one pound? The are so many fun units to choose from, only some of which are conveniently sized. How about a stick 1 mile long, or a rock that weights 1 grain?
I bet it's kind of going off of the original SI representation where, like, a foot was the length of the king's foot, and that was what they had to measure against to make sure everything was accurate.
The .50 BMG round can produce between 10,000 and 15,000 foot-pounds force (14,000 and 20,000 J), depending on its powder and bullet type, as well as the weapon it is fired from
Thats literally exactly what it is. They aren't derived from the metric system like all units in the system, theyre a specialized edge case where a conversion was specifically written in because america sucks. There are no other conversions in the metric system, units are derived from constants based on a set of specific rules that the pound and yard do not adhere to.