Not FOSS as far as I can tell. Maybe it’s no concern to folks running MS stuff already, but IMO closed-source is a red flag for trustworthiness.

Especially in a middle school math/physics setting, I would expect reasonable units. Otherwise, how would kids understand the relationship between force and acceleration? Do you use mile / hour / min for the acceleration due to gravity as well? Do you have a funky replacement for Newton too?

I didn’t get it for a solid 2 minutes before realizing you have to pronounce it wrong for the joke to work

That’s not the problem. Coming from metric, I expected m s^-2 for acceleration. The imperial units for distances are weird enough in their own right – but using two different units of time for the two time derivatives is truly unholy.

I was not ready for the truly unholy unit of mile per hour per minute

The natural representation would be the transient solution u(t) or i(t). Harmonic solutions are merely a special case, for which it turned out complex numbers were useful (because of the way they can represent rotation). They certainly serve a purpose there, but imo this is not an instance of ‘complex numbers appearing in nature’.

But that is hardly a ‘natural occurence’ of complex numbers - it just turned out that they were useful to represent the special case of harmonic solutions because of their relationship with trig functions.