I should specify when I say physical engineering I just mean chemical, mechanical, electrical, etc. (not software), rather than physics in theory/academia.

I guess engineers are applied physics (in a particular area each), and we need to distribute our deliverables to people who aren't necessarily experts in every discipline.

It just also makes sense to always define variables.

It's so funny because I've never seen voltage defined as U, and not V haha, proving how if you're going to have an equation, you'd better define everything, there's so many reused letters!

Thanks for sharing