Seeing as I’m a comp sci student, whenever I find myself in a situation requiring loads of repetition, I try and work out how to optimise the algorithm I am using for the situation. Usually, I can get something that most people would require O(n^2) down to at least O(n logn).
Funny you should mention this… This morning as I was getting out of bed and walking to school for the first time in a while (I usually bike), I was thinking about how ug - v^2/r = a when turning a bicycle.
As for you saying most people don’t calculate momentum in their heads for practical, mundane, purposes, that’s probably true. But you also probably don’t balance chemical equations or calculate solubility products while doing laundry or having sex. (Also, I don’t get it, if you’re saying chem = good, then why does chem blow? Yes, I realize the sexual connotation…)
Physics is definitely up there. Driving on snow? Drive slowly! Raining with wind in a constant direction? Point your umbrella into the wind. Etc.
I’d say anatomy is the most important, but then again its usefulness for daily things would probably decrease significantly after the basics, unless you’re a doctor.
As for n*log(2,n) decisions, I do, after all, use the merge sort algorithm to remove the flies from my cafe food :D.
Pretty much all sciences are useful to some extent, but I’d say the one that still becomes more and more practically useful as you learn more is physics.
My crappy resnet is slow again, but on preview (after loading the page off and on for the last 40 minutes), I meant usefulness in physics up to dynamics and such (e.g., the de Broglie wavelength of a car or Gaussian fields probably aren’t very useful to the average person). However, in that regard it’s probably still ahead of other subjects such as algebra or anatomy, which most people get all the usefulness out of before age 13.
Optics, chemistry, algebra. All part of photography and optics because I wear glasses.
Well, then stop it! v^2/r is not a force. It’s the acceleration that corresponds to moving in a circle. Never write: (forces) + v^2/r = a. It’s bad mojo.
(looks around)
Oh, um, right. To answer the question, I use physics more than anything else.
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That’s true. Me, I usually think about baseball.
Then you would have to also include physics. Thermodynamics!
That means you usually deal with special cases. 
Tangent: Thermodynamics I learned in my chemistry class, not my physics class (although it is related to physics).
Err, Giraffe, ug isn’t a force either.
umg - mv^2/r = ma
masses cancel. However, as for the actual equation, I was just playing around.
Anatomy(+ physiology, as a natural consequence since they are so interrelated).
next up would be physics i suppose. Intuitively of course. Riding a bike, driving, opening a door(leverage! ever try opening a door from the center?).
Ian Fan. you wouldn’t happen to attend the biketown capitol UC(UC davis) would ya?
For me it’s physics. I use it when solving engineering problems, and I use electronics science (analogue/digital circuits, diodes etc.) when designing circuits.
Physics, it stops me flying off at a tangent to the earth.
And it keeps my atoms together. And so on.